Changeset - 622cf123a4e6
[Not reviewed]
0 9 0
MH - 4 years ago 2021-05-27 18:56:55
contact@maxhenger.nl
Add concatenation assignment
6 files changed:
0 comments (0 inline, 0 general)
src/protocol/ast.rs
Show inline comments
 
@@ -514,1062 +514,1063 @@ impl Scope {
 
            Scope::Regular(_) => true,
 
            Scope::Synchronous(_) => true,
 
        }
 
    }
 
    pub fn to_block(&self) -> BlockStatementId {
 
        match &self {
 
            Scope::Regular(id) => *id,
 
            Scope::Synchronous((_, id)) => *id,
 
            _ => panic!("unable to get BlockStatement from Scope")
 
        }
 
    }
 
}
 

	
 
/// `ScopeNode` is a helper that links scopes in two directions. It doesn't
 
/// actually contain any information associated with the scope, this may be
 
/// found on the AST elements that `Scope` points to.
 
#[derive(Debug, Clone)]
 
pub struct ScopeNode {
 
    pub parent: Scope,
 
    pub nested: Vec<Scope>,
 
}
 

	
 
impl ScopeNode {
 
    pub(crate) fn new_invalid() -> Self {
 
        ScopeNode{
 
            parent: Scope::Definition(DefinitionId::new_invalid()),
 
            nested: Vec::new(),
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone, PartialEq, Eq)]
 
pub enum VariableKind {
 
    Parameter,      // in parameter list of function/component
 
    Local,          // declared in function/component body
 
    Binding,        // may be bound to in a binding expression (determined in validator/linker)
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct Variable {
 
    pub this: VariableId,
 
    // Parsing
 
    pub kind: VariableKind,
 
    pub parser_type: ParserType,
 
    pub identifier: Identifier,
 
    // Validator/linker
 
    pub relative_pos_in_block: u32,
 
    pub unique_id_in_scope: i32, // Temporary fix until proper bytecode/asm is generated
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Definition {
 
    Struct(StructDefinition),
 
    Enum(EnumDefinition),
 
    Union(UnionDefinition),
 
    Component(ComponentDefinition),
 
    Function(FunctionDefinition),
 
}
 

	
 
impl Definition {
 
    pub fn is_struct(&self) -> bool {
 
        match self {
 
            Definition::Struct(_) => true,
 
            _ => false
 
        }
 
    }
 
    pub(crate) fn as_struct(&self) -> &StructDefinition {
 
        match self {
 
            Definition::Struct(result) => result,
 
            _ => panic!("Unable to cast 'Definition' to 'StructDefinition'"),
 
        }
 
    }
 
    pub(crate) fn as_struct_mut(&mut self) -> &mut StructDefinition {
 
        match self {
 
            Definition::Struct(result) => result,
 
            _ => panic!("Unable to cast 'Definition' to 'StructDefinition'"),
 
        }
 
    }
 
    pub fn is_enum(&self) -> bool {
 
        match self {
 
            Definition::Enum(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub(crate) fn as_enum(&self) -> &EnumDefinition {
 
        match self {
 
            Definition::Enum(result) => result,
 
            _ => panic!("Unable to cast 'Definition' to 'EnumDefinition'"),
 
        }
 
    }
 
    pub(crate) fn as_enum_mut(&mut self) -> &mut EnumDefinition {
 
        match self {
 
            Definition::Enum(result) => result,
 
            _ => panic!("Unable to cast 'Definition' to 'EnumDefinition'"),
 
        }
 
    }
 
    pub fn is_union(&self) -> bool {
 
        match self {
 
            Definition::Union(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub(crate) fn as_union(&self) -> &UnionDefinition {
 
        match self {
 
            Definition::Union(result) => result, 
 
            _ => panic!("Unable to cast 'Definition' to 'UnionDefinition'"),
 
        }
 
    }
 
    pub(crate) fn as_union_mut(&mut self) -> &mut UnionDefinition {
 
        match self {
 
            Definition::Union(result) => result,
 
            _ => panic!("Unable to cast 'Definition' to 'UnionDefinition'"),
 
        }
 
    }
 
    pub fn is_component(&self) -> bool {
 
        match self {
 
            Definition::Component(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub(crate) fn as_component(&self) -> &ComponentDefinition {
 
        match self {
 
            Definition::Component(result) => result,
 
            _ => panic!("Unable to cast `Definition` to `Component`"),
 
        }
 
    }
 
    pub(crate) fn as_component_mut(&mut self) -> &mut ComponentDefinition {
 
        match self {
 
            Definition::Component(result) => result,
 
            _ => panic!("Unable to cast `Definition` to `Component`"),
 
        }
 
    }
 
    pub fn is_function(&self) -> bool {
 
        match self {
 
            Definition::Function(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub(crate) fn as_function(&self) -> &FunctionDefinition {
 
        match self {
 
            Definition::Function(result) => result,
 
            _ => panic!("Unable to cast `Definition` to `Function`"),
 
        }
 
    }
 
    pub(crate) fn as_function_mut(&mut self) -> &mut FunctionDefinition {
 
        match self {
 
            Definition::Function(result) => result,
 
            _ => panic!("Unable to cast `Definition` to `Function`"),
 
        }
 
    }
 
    pub fn parameters(&self) -> &Vec<VariableId> {
 
        match self {
 
            Definition::Component(def) => &def.parameters,
 
            Definition::Function(def) => &def.parameters,
 
            _ => panic!("Called parameters() on {:?}", self)
 
        }
 
    }
 
    pub fn defined_in(&self) -> RootId {
 
        match self {
 
            Definition::Struct(def) => def.defined_in,
 
            Definition::Enum(def) => def.defined_in,
 
            Definition::Union(def) => def.defined_in,
 
            Definition::Component(def) => def.defined_in,
 
            Definition::Function(def) => def.defined_in,
 
        }
 
    }
 
    pub fn identifier(&self) -> &Identifier {
 
        match self {
 
            Definition::Struct(def) => &def.identifier,
 
            Definition::Enum(def) => &def.identifier,
 
            Definition::Union(def) => &def.identifier,
 
            Definition::Component(def) => &def.identifier,
 
            Definition::Function(def) => &def.identifier,
 
        }
 
    }
 
    pub fn poly_vars(&self) -> &Vec<Identifier> {
 
        match self {
 
            Definition::Struct(def) => &def.poly_vars,
 
            Definition::Enum(def) => &def.poly_vars,
 
            Definition::Union(def) => &def.poly_vars,
 
            Definition::Component(def) => &def.poly_vars,
 
            Definition::Function(def) => &def.poly_vars,
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct StructFieldDefinition {
 
    pub span: InputSpan,
 
    pub field: Identifier,
 
    pub parser_type: ParserType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct StructDefinition {
 
    pub this: StructDefinitionId,
 
    pub defined_in: RootId,
 
    // Symbol scanning
 
    pub span: InputSpan,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    // Parsing
 
    pub fields: Vec<StructFieldDefinition>
 
}
 

	
 
impl StructDefinition {
 
    pub(crate) fn new_empty(
 
        this: StructDefinitionId, defined_in: RootId, span: InputSpan,
 
        identifier: Identifier, poly_vars: Vec<Identifier>
 
    ) -> Self {
 
        Self{ this, defined_in, span, identifier, poly_vars, fields: Vec::new() }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum EnumVariantValue {
 
    None,
 
    Integer(i64),
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct EnumVariantDefinition {
 
    pub identifier: Identifier,
 
    pub value: EnumVariantValue,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct EnumDefinition {
 
    pub this: EnumDefinitionId,
 
    pub defined_in: RootId,
 
    // Symbol scanning
 
    pub span: InputSpan,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    // Parsing
 
    pub variants: Vec<EnumVariantDefinition>,
 
}
 

	
 
impl EnumDefinition {
 
    pub(crate) fn new_empty(
 
        this: EnumDefinitionId, defined_in: RootId, span: InputSpan,
 
        identifier: Identifier, poly_vars: Vec<Identifier>
 
    ) -> Self {
 
        Self{ this, defined_in, span, identifier, poly_vars, variants: Vec::new() }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum UnionVariantValue {
 
    None,
 
    Embedded(Vec<ParserType>),
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct UnionVariantDefinition {
 
    pub span: InputSpan,
 
    pub identifier: Identifier,
 
    pub value: UnionVariantValue,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct UnionDefinition {
 
    pub this: UnionDefinitionId,
 
    pub defined_in: RootId,
 
    // Phase 1: symbol scanning
 
    pub span: InputSpan,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    // Phase 2: parsing
 
    pub variants: Vec<UnionVariantDefinition>,
 
}
 

	
 
impl UnionDefinition {
 
    pub(crate) fn new_empty(
 
        this: UnionDefinitionId, defined_in: RootId, span: InputSpan,
 
        identifier: Identifier, poly_vars: Vec<Identifier>
 
    ) -> Self {
 
        Self{ this, defined_in, span, identifier, poly_vars, variants: Vec::new() }
 
    }
 
}
 

	
 
#[derive(Debug, Clone, Copy)]
 
pub enum ComponentVariant {
 
    Primitive,
 
    Composite,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ComponentDefinition {
 
    pub this: ComponentDefinitionId,
 
    pub defined_in: RootId,
 
    // Symbol scanning
 
    pub span: InputSpan,
 
    pub variant: ComponentVariant,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    // Parsing
 
    pub parameters: Vec<VariableId>,
 
    pub body: BlockStatementId,
 
    // Validation/linking
 
    pub num_expressions_in_body: i32,
 
}
 

	
 
impl ComponentDefinition {
 
    // Used for preallocation during symbol scanning
 
    pub(crate) fn new_empty(
 
        this: ComponentDefinitionId, defined_in: RootId, span: InputSpan,
 
        variant: ComponentVariant, identifier: Identifier, poly_vars: Vec<Identifier>
 
    ) -> Self {
 
        Self{ 
 
            this, defined_in, span, variant, identifier, poly_vars,
 
            parameters: Vec::new(), 
 
            body: BlockStatementId::new_invalid(),
 
            num_expressions_in_body: -1,
 
        }
 
    }
 
}
 

	
 
// Note that we will have function definitions for builtin functions as well. In
 
// that case the span, the identifier span and the body are all invalid.
 
#[derive(Debug, Clone)]
 
pub struct FunctionDefinition {
 
    pub this: FunctionDefinitionId,
 
    pub defined_in: RootId,
 
    // Symbol scanning
 
    pub builtin: bool,
 
    pub span: InputSpan,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    // Parser
 
    pub return_types: Vec<ParserType>,
 
    pub parameters: Vec<VariableId>,
 
    pub body: BlockStatementId,
 
    // Validation/linking
 
    pub num_expressions_in_body: i32,
 
}
 

	
 
impl FunctionDefinition {
 
    pub(crate) fn new_empty(
 
        this: FunctionDefinitionId, defined_in: RootId, span: InputSpan,
 
        identifier: Identifier, poly_vars: Vec<Identifier>
 
    ) -> Self {
 
        Self {
 
            this, defined_in,
 
            builtin: false,
 
            span, identifier, poly_vars,
 
            return_types: Vec::new(),
 
            parameters: Vec::new(),
 
            body: BlockStatementId::new_invalid(),
 
            num_expressions_in_body: -1,
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Statement {
 
    Block(BlockStatement),
 
    EndBlock(EndBlockStatement),
 
    Local(LocalStatement),
 
    Labeled(LabeledStatement),
 
    If(IfStatement),
 
    EndIf(EndIfStatement),
 
    While(WhileStatement),
 
    EndWhile(EndWhileStatement),
 
    Break(BreakStatement),
 
    Continue(ContinueStatement),
 
    Synchronous(SynchronousStatement),
 
    EndSynchronous(EndSynchronousStatement),
 
    Return(ReturnStatement),
 
    Goto(GotoStatement),
 
    New(NewStatement),
 
    Expression(ExpressionStatement),
 
}
 

	
 
impl Statement {
 
    pub fn as_block(&self) -> &BlockStatement {
 
        match self {
 
            Statement::Block(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `BlockStatement`"),
 
        }
 
    }
 
    pub fn as_local(&self) -> &LocalStatement {
 
        match self {
 
            Statement::Local(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `LocalStatement`"),
 
        }
 
    }
 
    pub fn as_memory(&self) -> &MemoryStatement {
 
        self.as_local().as_memory()
 
    }
 
    pub fn as_channel(&self) -> &ChannelStatement {
 
        self.as_local().as_channel()
 
    }
 

	
 
    pub fn as_new(&self) -> &NewStatement {
 
        match self {
 
            Statement::New(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `NewStatement`"),
 
        }
 
    }
 

	
 
    pub fn span(&self) -> InputSpan {
 
        match self {
 
            Statement::Block(v) => v.span,
 
            Statement::Local(v) => v.span(),
 
            Statement::Labeled(v) => v.label.span,
 
            Statement::If(v) => v.span,
 
            Statement::While(v) => v.span,
 
            Statement::Break(v) => v.span,
 
            Statement::Continue(v) => v.span,
 
            Statement::Synchronous(v) => v.span,
 
            Statement::Return(v) => v.span,
 
            Statement::Goto(v) => v.span,
 
            Statement::New(v) => v.span,
 
            Statement::Expression(v) => v.span,
 
            Statement::EndBlock(_) | Statement::EndIf(_) | Statement::EndWhile(_) | Statement::EndSynchronous(_) => unreachable!(),
 
        }
 
    }
 
    pub fn link_next(&mut self, next: StatementId) {
 
        match self {
 
            Statement::Block(stmt) => stmt.next = next,
 
            Statement::EndBlock(stmt) => stmt.next = next,
 
            Statement::Local(stmt) => match stmt {
 
                LocalStatement::Channel(stmt) => stmt.next = next,
 
                LocalStatement::Memory(stmt) => stmt.next = next,
 
            },
 
            Statement::EndIf(stmt) => stmt.next = next,
 
            Statement::EndWhile(stmt) => stmt.next = next,
 
            Statement::EndSynchronous(stmt) => stmt.next = next,
 
            Statement::New(stmt) => stmt.next = next,
 
            Statement::Expression(stmt) => stmt.next = next,
 
            Statement::Return(_)
 
            | Statement::Break(_)
 
            | Statement::Continue(_)
 
            | Statement::Synchronous(_)
 
            | Statement::Goto(_)
 
            | Statement::While(_)
 
            | Statement::Labeled(_)
 
            | Statement::If(_) => unreachable!(),
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct BlockStatement {
 
    pub this: BlockStatementId,
 
    // Phase 1: parser
 
    pub is_implicit: bool,
 
    pub span: InputSpan, // of the complete block
 
    pub statements: Vec<StatementId>,
 
    pub end_block: EndBlockStatementId,
 
    // Phase 2: linker
 
    pub scope_node: ScopeNode,
 
    pub first_unique_id_in_scope: i32, // Temporary fix until proper bytecode/asm is generated
 
    pub next_unique_id_in_scope: i32, // Temporary fix until proper bytecode/asm is generated
 
    pub relative_pos_in_parent: u32,
 
    pub locals: Vec<VariableId>,
 
    pub labels: Vec<LabeledStatementId>,
 
    pub next: StatementId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct EndBlockStatement {
 
    pub this: EndBlockStatementId,
 
    // Parser
 
    pub start_block: BlockStatementId,
 
    // Validation/Linking
 
    pub next: StatementId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum LocalStatement {
 
    Memory(MemoryStatement),
 
    Channel(ChannelStatement),
 
}
 

	
 
impl LocalStatement {
 
    pub fn this(&self) -> LocalStatementId {
 
        match self {
 
            LocalStatement::Memory(stmt) => stmt.this.upcast(),
 
            LocalStatement::Channel(stmt) => stmt.this.upcast(),
 
        }
 
    }
 
    pub fn as_memory(&self) -> &MemoryStatement {
 
        match self {
 
            LocalStatement::Memory(result) => result,
 
            _ => panic!("Unable to cast `LocalStatement` to `MemoryStatement`"),
 
        }
 
    }
 
    pub fn as_channel(&self) -> &ChannelStatement {
 
        match self {
 
            LocalStatement::Channel(result) => result,
 
            _ => panic!("Unable to cast `LocalStatement` to `ChannelStatement`"),
 
        }
 
    }
 
    pub fn span(&self) -> InputSpan {
 
        match self {
 
            LocalStatement::Channel(v) => v.span,
 
            LocalStatement::Memory(v) => v.span,
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct MemoryStatement {
 
    pub this: MemoryStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub variable: VariableId,
 
    // Phase 2: linker
 
    pub next: StatementId,
 
}
 

	
 
/// ChannelStatement is the declaration of an input and output port associated
 
/// with the same channel. Note that the polarity of the ports are from the
 
/// point of view of the component. So an output port is something that a
 
/// component uses to send data over (i.e. it is the "input end" of the
 
/// channel), and vice versa.
 
#[derive(Debug, Clone)]
 
pub struct ChannelStatement {
 
    pub this: ChannelStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "channel" keyword
 
    pub from: VariableId, // output
 
    pub to: VariableId,   // input
 
    // Phase 2: linker
 
    pub relative_pos_in_block: u32,
 
    pub next: StatementId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LabeledStatement {
 
    pub this: LabeledStatementId,
 
    // Phase 1: parser
 
    pub label: Identifier,
 
    pub body: StatementId,
 
    // Phase 2: linker
 
    pub relative_pos_in_block: u32,
 
    pub in_sync: SynchronousStatementId, // may be invalid
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct IfStatement {
 
    pub this: IfStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "if" keyword
 
    pub test: ExpressionId,
 
    pub true_body: BlockStatementId,
 
    pub false_body: Option<BlockStatementId>,
 
    pub end_if: EndIfStatementId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct EndIfStatement {
 
    pub this: EndIfStatementId,
 
    pub start_if: IfStatementId,
 
    pub next: StatementId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct WhileStatement {
 
    pub this: WhileStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "while" keyword
 
    pub test: ExpressionId,
 
    pub body: BlockStatementId,
 
    pub end_while: EndWhileStatementId,
 
    pub in_sync: SynchronousStatementId, // may be invalid
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct EndWhileStatement {
 
    pub this: EndWhileStatementId,
 
    pub start_while: WhileStatementId,
 
    // Phase 2: linker
 
    pub next: StatementId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct BreakStatement {
 
    pub this: BreakStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "break" keyword
 
    pub label: Option<Identifier>,
 
    // Phase 2: linker
 
    pub target: Option<EndWhileStatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ContinueStatement {
 
    pub this: ContinueStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "continue" keyword
 
    pub label: Option<Identifier>,
 
    // Phase 2: linker
 
    pub target: Option<WhileStatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct SynchronousStatement {
 
    pub this: SynchronousStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "sync" keyword
 
    pub body: BlockStatementId,
 
    // Phase 2: linker
 
    pub end_sync: EndSynchronousStatementId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct EndSynchronousStatement {
 
    pub this: EndSynchronousStatementId,
 
    pub start_sync: SynchronousStatementId,
 
    // Phase 2: linker
 
    pub next: StatementId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ReturnStatement {
 
    pub this: ReturnStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "return" keyword
 
    pub expressions: Vec<ExpressionId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct GotoStatement {
 
    pub this: GotoStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "goto" keyword
 
    pub label: Identifier,
 
    // Phase 2: linker
 
    pub target: Option<LabeledStatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct NewStatement {
 
    pub this: NewStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "new" keyword
 
    pub expression: CallExpressionId,
 
    // Phase 2: linker
 
    pub next: StatementId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ExpressionStatement {
 
    pub this: ExpressionStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub expression: ExpressionId,
 
    // Phase 2: linker
 
    pub next: StatementId,
 
}
 

	
 
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
 
pub enum ExpressionParent {
 
    None, // only set during initial parsing
 
    If(IfStatementId),
 
    While(WhileStatementId),
 
    Return(ReturnStatementId),
 
    New(NewStatementId),
 
    ExpressionStmt(ExpressionStatementId),
 
    Expression(ExpressionId, u32) // index within expression (e.g LHS or RHS of expression)
 
}
 

	
 
impl ExpressionParent {
 
    pub fn is_new(&self) -> bool {
 
        match self {
 
            ExpressionParent::New(_) => true,
 
            _ => false,
 
        }
 
    }
 

	
 
    pub fn as_expression(&self) -> ExpressionId {
 
        match self {
 
            ExpressionParent::Expression(id, _) => *id,
 
            _ => panic!("called as_expression() on {:?}", self),
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Expression {
 
    Assignment(AssignmentExpression),
 
    Binding(BindingExpression),
 
    Conditional(ConditionalExpression),
 
    Binary(BinaryExpression),
 
    Unary(UnaryExpression),
 
    Indexing(IndexingExpression),
 
    Slicing(SlicingExpression),
 
    Select(SelectExpression),
 
    Literal(LiteralExpression),
 
    Cast(CastExpression),
 
    Call(CallExpression),
 
    Variable(VariableExpression),
 
}
 

	
 
impl Expression {
 
    pub fn as_variable(&self) -> &VariableExpression {
 
        match self {
 
            Expression::Variable(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `VariableExpression`"),
 
        }
 
    }
 

	
 
    pub fn span(&self) -> InputSpan {
 
        match self {
 
            Expression::Assignment(expr) => expr.span,
 
            Expression::Binding(expr) => expr.span,
 
            Expression::Conditional(expr) => expr.span,
 
            Expression::Binary(expr) => expr.span,
 
            Expression::Unary(expr) => expr.span,
 
            Expression::Indexing(expr) => expr.span,
 
            Expression::Slicing(expr) => expr.span,
 
            Expression::Select(expr) => expr.span,
 
            Expression::Literal(expr) => expr.span,
 
            Expression::Cast(expr) => expr.span,
 
            Expression::Call(expr) => expr.span,
 
            Expression::Variable(expr) => expr.identifier.span,
 
        }
 
    }
 
    // TODO: @cleanup
 
    pub fn parent(&self) -> &ExpressionParent {
 
        match self {
 
            Expression::Assignment(expr) => &expr.parent,
 
            Expression::Binding(expr) => &expr.parent,
 
            Expression::Conditional(expr) => &expr.parent,
 
            Expression::Binary(expr) => &expr.parent,
 
            Expression::Unary(expr) => &expr.parent,
 
            Expression::Indexing(expr) => &expr.parent,
 
            Expression::Slicing(expr) => &expr.parent,
 
            Expression::Select(expr) => &expr.parent,
 
            Expression::Literal(expr) => &expr.parent,
 
            Expression::Cast(expr) => &expr.parent,
 
            Expression::Call(expr) => &expr.parent,
 
            Expression::Variable(expr) => &expr.parent,
 
        }
 
    }
 
    // TODO: @cleanup
 
    pub fn parent_expr_id(&self) -> Option<ExpressionId> {
 
        if let ExpressionParent::Expression(id, _) = self.parent() {
 
            Some(*id)
 
        } else {
 
            None
 
        }
 
    }
 

	
 
    pub fn get_unique_id_in_definition(&self) -> i32 {
 
        match self {
 
            Expression::Assignment(expr) => expr.unique_id_in_definition,
 
            Expression::Binding(expr) => expr.unique_id_in_definition,
 
            Expression::Conditional(expr) => expr.unique_id_in_definition,
 
            Expression::Binary(expr) => expr.unique_id_in_definition,
 
            Expression::Unary(expr) => expr.unique_id_in_definition,
 
            Expression::Indexing(expr) => expr.unique_id_in_definition,
 
            Expression::Slicing(expr) => expr.unique_id_in_definition,
 
            Expression::Select(expr) => expr.unique_id_in_definition,
 
            Expression::Literal(expr) => expr.unique_id_in_definition,
 
            Expression::Cast(expr) => expr.unique_id_in_definition,
 
            Expression::Call(expr) => expr.unique_id_in_definition,
 
            Expression::Variable(expr) => expr.unique_id_in_definition,
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone, Copy)]
 
pub enum AssignmentOperator {
 
    Set,
 
    Concatenated,
 
    Multiplied,
 
    Divided,
 
    Remained,
 
    Added,
 
    Subtracted,
 
    ShiftedLeft,
 
    ShiftedRight,
 
    BitwiseAnded,
 
    BitwiseXored,
 
    BitwiseOred,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct AssignmentExpression {
 
    pub this: AssignmentExpressionId,
 
    // Parsing
 
    pub span: InputSpan, // of the operator
 
    pub left: ExpressionId,
 
    pub operation: AssignmentOperator,
 
    pub right: ExpressionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct BindingExpression {
 
    pub this: BindingExpressionId,
 
    // Parsing
 
    pub span: InputSpan, // of the binding keyword
 
    pub bound_to: ExpressionId,
 
    pub bound_from: ExpressionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ConditionalExpression {
 
    pub this: ConditionalExpressionId,
 
    // Parsing
 
    pub span: InputSpan, // of question mark operator
 
    pub test: ExpressionId,
 
    pub true_expression: ExpressionId,
 
    pub false_expression: ExpressionId,
 
    // Validator/Linking
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
 
pub enum BinaryOperator {
 
    Concatenate,
 
    LogicalOr,
 
    LogicalAnd,
 
    BitwiseOr,
 
    BitwiseXor,
 
    BitwiseAnd,
 
    Equality,
 
    Inequality,
 
    LessThan,
 
    GreaterThan,
 
    LessThanEqual,
 
    GreaterThanEqual,
 
    ShiftLeft,
 
    ShiftRight,
 
    Add,
 
    Subtract,
 
    Multiply,
 
    Divide,
 
    Remainder,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct BinaryExpression {
 
    pub this: BinaryExpressionId,
 
    // Parsing
 
    pub span: InputSpan, // of the operator
 
    pub left: ExpressionId,
 
    pub operation: BinaryOperator,
 
    pub right: ExpressionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
 
pub enum UnaryOperator {
 
    Positive,
 
    Negative,
 
    BitwiseNot,
 
    LogicalNot,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct UnaryExpression {
 
    pub this: UnaryExpressionId,
 
    // Parsing
 
    pub span: InputSpan, // of the operator
 
    pub operation: UnaryOperator,
 
    pub expression: ExpressionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct IndexingExpression {
 
    pub this: IndexingExpressionId,
 
    // Parsing
 
    pub span: InputSpan,
 
    pub subject: ExpressionId,
 
    pub index: ExpressionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct SlicingExpression {
 
    pub this: SlicingExpressionId,
 
    // Parsing
 
    pub span: InputSpan, // from '[' to ']';
 
    pub subject: ExpressionId,
 
    pub from_index: ExpressionId,
 
    pub to_index: ExpressionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct SelectExpression {
 
    pub this: SelectExpressionId,
 
    // Parsing
 
    pub span: InputSpan, // of the '.'
 
    pub subject: ExpressionId,
 
    pub field_name: Identifier,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct CastExpression {
 
    pub this: CastExpressionId,
 
    // Parsing
 
    pub span: InputSpan, // of the "cast" keyword,
 
    pub to_type: ParserType,
 
    pub subject: ExpressionId,
 
    // Validator/linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct CallExpression {
 
    pub this: CallExpressionId,
 
    // Parsing
 
    pub span: InputSpan,
 
    pub parser_type: ParserType, // of the function call, not the return type
 
    pub method: Method,
 
    pub arguments: Vec<ExpressionId>,
 
    pub definition: DefinitionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone, PartialEq, Eq)]
 
pub enum Method {
 
    // Builtin
 
    Get,
 
    Put,
 
    Fires,
 
    Create,
 
    Length,
 
    Assert,
 
    UserFunction,
 
    UserComponent,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct MethodSymbolic {
 
    pub(crate) parser_type: ParserType,
 
    pub(crate) definition: DefinitionId
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralExpression {
 
    pub this: LiteralExpressionId,
 
    // Parsing
 
    pub span: InputSpan,
 
    pub value: Literal,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Literal {
 
    Null, // message
 
    True,
 
    False,
 
    Character(char),
 
    String(StringRef<'static>),
 
    Integer(LiteralInteger),
 
    Struct(LiteralStruct),
 
    Enum(LiteralEnum),
 
    Union(LiteralUnion),
 
    Array(Vec<ExpressionId>),
 
}
 

	
 
impl Literal {
 
    pub(crate) fn as_struct(&self) -> &LiteralStruct {
 
        if let Literal::Struct(literal) = self{
 
            literal
 
        } else {
 
            unreachable!("Attempted to obtain {:?} as Literal::Struct", self)
 
        }
 
    }
 

	
 
    pub(crate) fn as_enum(&self) -> &LiteralEnum {
 
        if let Literal::Enum(literal) = self {
 
            literal
 
        } else {
 
            unreachable!("Attempted to obtain {:?} as Literal::Enum", self)
 
        }
 
    }
 

	
 
    pub(crate) fn as_union(&self) -> &LiteralUnion {
 
        if let Literal::Union(literal) = self {
 
            literal
 
        } else {
 
            unreachable!("Attempted to obtain {:?} as Literal::Union", self)
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralInteger {
 
    pub(crate) unsigned_value: u64,
 
    pub(crate) negated: bool, // for constant expression evaluation, TODO: @Int
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralStructField {
 
    // Phase 1: parser
 
    pub(crate) identifier: Identifier,
 
    pub(crate) value: ExpressionId,
 
    // Phase 2: linker
 
    pub(crate) field_idx: usize, // in struct definition
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralStruct {
 
    // Phase 1: parser
 
    pub(crate) parser_type: ParserType,
 
    pub(crate) fields: Vec<LiteralStructField>,
 
    pub(crate) definition: DefinitionId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralEnum {
 
    // Phase 1: parser
 
    pub(crate) parser_type: ParserType,
 
    pub(crate) variant: Identifier,
 
    pub(crate) definition: DefinitionId,
 
    // Phase 2: linker
 
    pub(crate) variant_idx: usize, // as present in the type table
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralUnion {
 
    // Phase 1: parser
 
    pub(crate) parser_type: ParserType,
 
    pub(crate) variant: Identifier,
 
    pub(crate) values: Vec<ExpressionId>,
 
    pub(crate) definition: DefinitionId,
 
    // Phase 2: linker
 
    pub(crate) variant_idx: usize, // as present in type table
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct VariableExpression {
 
    pub this: VariableExpressionId,
 
    // Parsing
 
    pub identifier: Identifier,
 
    // Validator/Linker
 
    pub declaration: Option<VariableId>,
 
    pub used_as_binding_target: bool,
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 
\ No newline at end of file
src/protocol/eval/executor.rs
Show inline comments
 

	
 
use std::collections::VecDeque;
 

	
 
use super::value::*;
 
use super::store::*;
 
use super::error::*;
 
use crate::protocol::*;
 
use crate::protocol::ast::*;
 
use crate::protocol::type_table::*;
 

	
 
macro_rules! debug_enabled { () => { false }; }
 
macro_rules! debug_log {
 
    ($format:literal) => {
 
        enabled_debug_print!(false, "exec", $format);
 
    };
 
    ($format:literal, $($args:expr),*) => {
 
        enabled_debug_print!(false, "exec", $format, $($args),*);
 
    };
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub(crate) enum ExprInstruction {
 
    EvalExpr(ExpressionId),
 
    PushValToFront,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub(crate) struct Frame {
 
    pub(crate) definition: DefinitionId,
 
    pub(crate) monomorph_idx: i32,
 
    pub(crate) position: StatementId,
 
    pub(crate) expr_stack: VecDeque<ExprInstruction>, // hack for expression evaluation, evaluated by popping from back
 
    pub(crate) expr_values: VecDeque<Value>, // hack for expression results, evaluated by popping from front/back
 
    pub(crate) max_stack_size: u32,
 
}
 

	
 
impl Frame {
 
    /// Creates a new execution frame. Does not modify the stack in any way.
 
    pub fn new(heap: &Heap, definition_id: DefinitionId, monomorph_idx: i32) -> Self {
 
        let definition = &heap[definition_id];
 
        let first_statement = match definition {
 
            Definition::Component(definition) => definition.body,
 
            Definition::Function(definition) => definition.body,
 
            _ => unreachable!("initializing frame with {:?} instead of a function/component", definition),
 
        };
 

	
 
        // Another not-so-pretty thing that has to be replaced somewhere in the
 
        // future...
 
        fn determine_max_stack_size(heap: &Heap, block_id: BlockStatementId, max_size: &mut u32) {
 
            let block_stmt = &heap[block_id];
 
            debug_assert!(block_stmt.next_unique_id_in_scope >= 0);
 

	
 
            // Check current block
 
            let cur_size = block_stmt.next_unique_id_in_scope as u32;
 
            if cur_size > *max_size { *max_size = cur_size; }
 

	
 
            // And child blocks
 
            for child_scope in &block_stmt.scope_node.nested {
 
                determine_max_stack_size(heap, child_scope.to_block(), max_size);
 
            }
 
        }
 

	
 
        let mut max_stack_size = 0;
 
        determine_max_stack_size(heap, first_statement, &mut max_stack_size);
 

	
 
        Frame{
 
            definition: definition_id,
 
            monomorph_idx,
 
            position: first_statement.upcast(),
 
            expr_stack: VecDeque::with_capacity(128),
 
            expr_values: VecDeque::with_capacity(128),
 
            max_stack_size,
 
        }
 
    }
 

	
 
    /// Prepares a single expression for execution. This involves walking the
 
    /// expression tree and putting them in the `expr_stack` such that
 
    /// continuously popping from its back will evaluate the expression. The
 
    /// results of each expression will be stored by pushing onto `expr_values`.
 
    pub fn prepare_single_expression(&mut self, heap: &Heap, expr_id: ExpressionId) {
 
        debug_assert!(self.expr_stack.is_empty());
 
        self.expr_values.clear(); // May not be empty if last expression result(s) were discarded
 

	
 
        self.serialize_expression(heap, expr_id);
 
    }
 

	
 
    /// Prepares multiple expressions for execution (i.e. evaluating all
 
    /// function arguments or all elements of an array/union literal). Per
 
    /// expression this works the same as `prepare_single_expression`. However
 
    /// after each expression is evaluated we insert a `PushValToFront`
 
    /// instruction
 
    pub fn prepare_multiple_expressions(&mut self, heap: &Heap, expr_ids: &[ExpressionId]) {
 
        debug_assert!(self.expr_stack.is_empty());
 
        self.expr_values.clear();
 

	
 
        for expr_id in expr_ids {
 
            self.expr_stack.push_back(ExprInstruction::PushValToFront);
 
            self.serialize_expression(heap, *expr_id);
 
        }
 
    }
 

	
 
    /// Performs depth-first serialization of expression tree. Let's not care
 
    /// about performance for a temporary runtime implementation
 
    fn serialize_expression(&mut self, heap: &Heap, id: ExpressionId) {
 
        self.expr_stack.push_back(ExprInstruction::EvalExpr(id));
 

	
 
        match &heap[id] {
 
            Expression::Assignment(expr) => {
 
                self.serialize_expression(heap, expr.left);
 
                self.serialize_expression(heap, expr.right);
 
            },
 
            Expression::Binding(expr) => {
 
                self.serialize_expression(heap, expr.bound_to);
 
                self.serialize_expression(heap, expr.bound_from);
 
            },
 
            Expression::Conditional(expr) => {
 
                self.serialize_expression(heap, expr.test);
 
            },
 
            Expression::Binary(expr) => {
 
                self.serialize_expression(heap, expr.left);
 
                self.serialize_expression(heap, expr.right);
 
            },
 
            Expression::Unary(expr) => {
 
                self.serialize_expression(heap, expr.expression);
 
            },
 
            Expression::Indexing(expr) => {
 
                self.serialize_expression(heap, expr.index);
 
                self.serialize_expression(heap, expr.subject);
 
            },
 
            Expression::Slicing(expr) => {
 
                self.serialize_expression(heap, expr.from_index);
 
                self.serialize_expression(heap, expr.to_index);
 
                self.serialize_expression(heap, expr.subject);
 
            },
 
            Expression::Select(expr) => {
 
                self.serialize_expression(heap, expr.subject);
 
            },
 
            Expression::Literal(expr) => {
 
                // Here we only care about literals that have subexpressions
 
                match &expr.value {
 
                    Literal::Null | Literal::True | Literal::False |
 
                    Literal::Character(_) | Literal::String(_) |
 
                    Literal::Integer(_) | Literal::Enum(_) => {
 
                        // No subexpressions
 
                    },
 
                    Literal::Struct(literal) => {
 
                        // Note: fields expressions are evaluated in programmer-
 
                        // specified order. But struct construction expects them
 
                        // in type-defined order. I might want to come back to
 
                        // this.
 
                        let mut _num_pushed = 0;
 
                        for want_field_idx in 0..literal.fields.len() {
 
                            for field in &literal.fields {
 
                                if field.field_idx == want_field_idx {
 
                                    _num_pushed += 1;
 
                                    self.expr_stack.push_back(ExprInstruction::PushValToFront);
 
                                    self.serialize_expression(heap, field.value);
 
                                }
 
                            }
 
                        }
 
                        debug_assert_eq!(_num_pushed, literal.fields.len())
 
                    },
 
                    Literal::Union(literal) => {
 
                        for value_expr_id in &literal.values {
 
                            self.expr_stack.push_back(ExprInstruction::PushValToFront);
 
                            self.serialize_expression(heap, *value_expr_id);
 
                        }
 
                    },
 
                    Literal::Array(value_expr_ids) => {
 
                        for value_expr_id in value_expr_ids {
 
                            self.expr_stack.push_back(ExprInstruction::PushValToFront);
 
                            self.serialize_expression(heap, *value_expr_id);
 
                        }
 
                    }
 
                }
 
            },
 
            Expression::Cast(expr) => {
 
                self.serialize_expression(heap, expr.subject);
 
            }
 
            Expression::Call(expr) => {
 
                for arg_expr_id in &expr.arguments {
 
                    self.expr_stack.push_back(ExprInstruction::PushValToFront);
 
                    self.serialize_expression(heap, *arg_expr_id);
 
                }
 
            },
 
            Expression::Variable(_expr) => {
 
                // No subexpressions
 
            }
 
        }
 
    }
 
}
 

	
 
type EvalResult = Result<EvalContinuation, EvalError>;
 

	
 
pub enum EvalContinuation {
 
    Stepping,
 
    Inconsistent,
 
    Terminal,
 
    SyncBlockStart,
 
    SyncBlockEnd,
 
    NewComponent(DefinitionId, i32, ValueGroup),
 
    BlockFires(Value),
 
    BlockGet(Value),
 
    Put(Value, Value),
 
}
 

	
 
// Note: cloning is fine, methinks. cloning all values and the heap regions then
 
// we end up with valid "pointers" to heap regions.
 
#[derive(Debug, Clone)]
 
pub struct Prompt {
 
    pub(crate) frames: Vec<Frame>,
 
    pub(crate) store: Store,
 
}
 

	
 
impl Prompt {
 
    pub fn new(_types: &TypeTable, heap: &Heap, def: DefinitionId, monomorph_idx: i32, args: ValueGroup) -> Self {
 
        let mut prompt = Self{
 
            frames: Vec::new(),
 
            store: Store::new(),
 
        };
 

	
 
        // Maybe do typechecking in the future?
 
        debug_assert!((monomorph_idx as usize) < _types.get_base_definition(&def).unwrap().definition.procedure_monomorphs().len());
 
        let new_frame = Frame::new(heap, def, monomorph_idx);
 
        let max_stack_size = new_frame.max_stack_size;
 
        prompt.frames.push(new_frame);
 
        args.into_store(&mut prompt.store);
 
        prompt.store.reserve_stack(max_stack_size);
 

	
 
        prompt
 
    }
 

	
 
    pub(crate) fn step(&mut self, types: &TypeTable, heap: &Heap, modules: &[Module], ctx: &mut EvalContext) -> EvalResult {
 
        // Helper function to transfer multiple values from the expression value
 
        // array into a heap region (e.g. constructing arrays or structs).
 
        fn transfer_expression_values_front_into_heap(cur_frame: &mut Frame, store: &mut Store, num_values: usize) -> HeapPos {
 
            let heap_pos = store.alloc_heap();
 

	
 
            // Do the transformation first (because Rust...)
 
            for val_idx in 0..num_values {
 
                cur_frame.expr_values[val_idx] = store.read_take_ownership(cur_frame.expr_values[val_idx].clone());
 
            }
 

	
 
            // And now transfer to the heap region
 
            let values = &mut store.heap_regions[heap_pos as usize].values;
 
            debug_assert!(values.is_empty());
 
            values.reserve(num_values);
 
            for _ in 0..num_values {
 
                values.push(cur_frame.expr_values.pop_front().unwrap());
 
            }
 

	
 
            heap_pos
 
        }
 

	
 
        // Helper function to make sure that an index into an aray is valid.
 
        fn array_inclusive_index_is_invalid(store: &Store, array_heap_pos: u32, idx: i64) -> bool {
 
            let array_len = store.heap_regions[array_heap_pos as usize].values.len();
 
            return idx < 0 || idx >= array_len as i64;
 
        }
 

	
 
        fn array_exclusive_index_is_invalid(store: &Store, array_heap_pos: u32, idx: i64) -> bool {
 
            let array_len = store.heap_regions[array_heap_pos as usize].values.len();
 
            return idx < 0 || idx > array_len as i64;
 
        }
 

	
 
        fn construct_array_error(prompt: &Prompt, modules: &[Module], heap: &Heap, expr_id: ExpressionId, heap_pos: u32, idx: i64) -> EvalError {
 
            let array_len = prompt.store.heap_regions[heap_pos as usize].values.len();
 
            return EvalError::new_error_at_expr(
 
                prompt, modules, heap, expr_id,
 
                format!("index {} is out of bounds: array length is {}", idx, array_len)
 
            )
 
        }
 

	
 
        // Checking if we're at the end of execution
 
        let cur_frame = self.frames.last_mut().unwrap();
 
        if cur_frame.position.is_invalid() {
 
            if heap[cur_frame.definition].is_function() {
 
                todo!("End of function without return, return an evaluation error");
 
            }
 
            return Ok(EvalContinuation::Terminal);
 
        }
 

	
 
        debug_log!("Taking step in '{}'", heap[cur_frame.definition].identifier().value.as_str());
 

	
 
        // Execute all pending expressions
 
        while !cur_frame.expr_stack.is_empty() {
 
            let next = cur_frame.expr_stack.pop_back().unwrap();
 
            debug_log!("Expr stack: {:?}", next);
 
            match next {
 
                ExprInstruction::PushValToFront => {
 
                    cur_frame.expr_values.rotate_right(1);
 
                },
 
                ExprInstruction::EvalExpr(expr_id) => {
 
                    let expr = &heap[expr_id];
 
                    match expr {
 
                        Expression::Assignment(expr) => {
 
                            let to = cur_frame.expr_values.pop_back().unwrap().as_ref();
 
                            let rhs = cur_frame.expr_values.pop_back().unwrap();
 

	
 
                            // Note: although not pretty, the assignment operator takes ownership
 
                            // of the right-hand side value when possible. So we do not drop the
 
                            // rhs's optionally owned heap data.
 
                            let rhs = self.store.read_take_ownership(rhs);
 
                            apply_assignment_operator(&mut self.store, to, expr.operation, rhs);
 
                        },
 
                        Expression::Binding(_expr) => {
 
                            let bind_to = cur_frame.expr_values.pop_back().unwrap();
 
                            let bind_from = cur_frame.expr_values.pop_back().unwrap();
 
                            let bind_to_heap_pos = bind_to.get_heap_pos();
 
                            let bind_from_heap_pos = bind_from.get_heap_pos();
 

	
 
                            let result = apply_binding_operator(&mut self.store, bind_to, bind_from);
 
                            self.store.drop_value(bind_to_heap_pos);
 
                            self.store.drop_value(bind_from_heap_pos);
 
                            cur_frame.expr_values.push_back(Value::Bool(result));
 
                        },
 
                        Expression::Conditional(expr) => {
 
                            // Evaluate testing expression, then extend the
 
                            // expression stack with the appropriate expression
 
                            let test_result = cur_frame.expr_values.pop_back().unwrap().as_bool();
 
                            if test_result {
 
                                cur_frame.serialize_expression(heap, expr.true_expression);
 
                            } else {
 
                                cur_frame.serialize_expression(heap, expr.false_expression);
 
                            }
 
                        },
 
                        Expression::Binary(expr) => {
 
                            let lhs = cur_frame.expr_values.pop_back().unwrap();
 
                            let rhs = cur_frame.expr_values.pop_back().unwrap();
 
                            let result = apply_binary_operator(&mut self.store, &lhs, expr.operation, &rhs);
 
                            cur_frame.expr_values.push_back(result);
 
                            self.store.drop_value(lhs.get_heap_pos());
 
                            self.store.drop_value(rhs.get_heap_pos());
 
                        },
 
                        Expression::Unary(expr) => {
 
                            let val = cur_frame.expr_values.pop_back().unwrap();
 
                            let result = apply_unary_operator(&mut self.store, expr.operation, &val);
 
                            cur_frame.expr_values.push_back(result);
 
                            self.store.drop_value(val.get_heap_pos());
 
                        },
 
                        Expression::Indexing(_expr) => {
 
                            // Evaluate index. Never heap allocated so we do
 
                            // not have to drop it.
 
                            let index = cur_frame.expr_values.pop_back().unwrap();
 
                            let index = self.store.maybe_read_ref(&index);
 

	
 
                            debug_assert!(index.is_integer());
 
                            let index = if index.is_signed_integer() {
 
                                index.as_signed_integer() as i64
 
                            } else {
 
                                index.as_unsigned_integer() as i64
 
                            };
 

	
 
                            let subject = cur_frame.expr_values.pop_back().unwrap();
 

	
 
                            let (deallocate_heap_pos, value_to_push) = match subject {
 
                                Value::Ref(value_ref) => {
 
                                    // Our expression stack value is a reference to something that
 
                                    // exists in the normal stack/heap. We don't want to deallocate
 
                                    // this thing. Rather we want to return a reference to it.
 
                                    let subject = self.store.read_ref(value_ref);
 
                                    let subject_heap_pos = match subject {
 
                                        Value::String(v) => *v,
 
                                        Value::Array(v) => *v,
 
                                        Value::Message(v) => *v,
 
                                        _ => unreachable!(),
 
                                    };
 

	
 
                                    if array_inclusive_index_is_invalid(&self.store, subject_heap_pos, index) {
 
                                        return Err(construct_array_error(self, modules, heap, expr_id, subject_heap_pos, index));
 
                                    }
 

	
 
                                    (None, Value::Ref(ValueId::Heap(subject_heap_pos, index as u32)))
 
                                },
 
                                _ => {
 
                                    // Our value lives on the expression stack, hence we need to
 
                                    // clone whatever we're referring to. Then drop the subject.
 
                                    let subject_heap_pos = match &subject {
 
                                        Value::String(v) => *v,
 
                                        Value::Array(v) => *v,
 
                                        Value::Message(v) => *v,
 
                                        _ => unreachable!(),
 
                                    };
 

	
 
                                    if array_inclusive_index_is_invalid(&self.store, subject_heap_pos, index) {
 
                                        return Err(construct_array_error(self, modules, heap, expr_id, subject_heap_pos, index));
 
                                    }
 

	
 
                                    let subject_indexed = Value::Ref(ValueId::Heap(subject_heap_pos, index as u32));
 
                                    (Some(subject_heap_pos), self.store.clone_value(subject_indexed))
 
                                },
 
                            };
 

	
 
                            cur_frame.expr_values.push_back(value_to_push);
 
                            self.store.drop_value(deallocate_heap_pos);
 
                        },
 
                        Expression::Slicing(expr) => {
 
                            // Evaluate indices
 
                            let from_index = cur_frame.expr_values.pop_back().unwrap();
 
                            let from_index = self.store.maybe_read_ref(&from_index);
 
                            let to_index = cur_frame.expr_values.pop_back().unwrap();
 
                            let to_index = self.store.maybe_read_ref(&to_index);
 

	
 
                            debug_assert!(from_index.is_integer() && to_index.is_integer());
 
                            let from_index = if from_index.is_signed_integer() {
 
                                from_index.as_signed_integer()
 
                            } else {
 
                                from_index.as_unsigned_integer() as i64
 
                            };
 
                            let to_index = if to_index.is_signed_integer() {
 
                                to_index.as_signed_integer()
 
                            } else {
 
                                to_index.as_unsigned_integer() as i64
 
                            };
 

	
 
                            // Dereference subject if needed
 
                            let subject = cur_frame.expr_values.pop_back().unwrap();
 
                            let deref_subject = self.store.maybe_read_ref(&subject);
 

	
 
                            // Slicing needs to produce a copy anyway (with the
 
                            // current evaluator implementation)
 
                            enum ValueKind{ Array, String, Message }
 
                            let (value_kind, array_heap_pos) = match deref_subject {
 
                                Value::Array(v) => (ValueKind::Array, *v),
 
                                Value::String(v) => (ValueKind::String, *v),
 
                                Value::Message(v) => (ValueKind::Message, *v),
 
                                _ => unreachable!()
 
                            };
 

	
 
                            if array_inclusive_index_is_invalid(&self.store, array_heap_pos, from_index) {
 
                                return Err(construct_array_error(self, modules, heap, expr.from_index, array_heap_pos, from_index));
 
                            }
 
                            if array_exclusive_index_is_invalid(&self.store, array_heap_pos, to_index) {
 
                                return Err(construct_array_error(self, modules, heap, expr.to_index, array_heap_pos, to_index));
 
                            }
 

	
 
                            // Again: would love to push directly, but rust...
 
                            let new_heap_pos = self.store.alloc_heap();
 
                            debug_assert!(self.store.heap_regions[new_heap_pos as usize].values.is_empty());
 
                            if to_index > from_index {
 
                                let from_index = from_index as usize;
 
                                let to_index = to_index as usize;
 
                                let mut values = Vec::with_capacity(to_index - from_index);
 
                                for idx in from_index..to_index {
 
                                    let value = self.store.heap_regions[array_heap_pos as usize].values[idx].clone();
 
                                    values.push(self.store.clone_value(value));
 
                                }
 

	
 
                                self.store.heap_regions[new_heap_pos as usize].values = values;
 

	
 
                            } // else: empty range
 

	
 
                            cur_frame.expr_values.push_back(match value_kind {
 
                                ValueKind::Array => Value::Array(new_heap_pos),
 
                                ValueKind::String => Value::String(new_heap_pos),
 
                                ValueKind::Message => Value::Message(new_heap_pos),
 
                            });
 

	
 
                            // Dropping the original subject, because we don't
 
                            // want to drop something on the stack
 
                            self.store.drop_value(subject.get_heap_pos());
 
                        },
 
                        Expression::Select(expr) => {
 
                            let subject= cur_frame.expr_values.pop_back().unwrap();
 
                            let mono_data = types.get_procedure_expression_data(&cur_frame.definition, cur_frame.monomorph_idx);
 
                            let field_idx = mono_data.expr_data[expr.unique_id_in_definition as usize].field_or_monomorph_idx as u32;
 

	
 
                            // Note: same as above: clone if value lives on expr stack, simply
 
                            // refer to it if it already lives on the stack/heap.
 
                            let (deallocate_heap_pos, value_to_push) = match subject {
 
                                Value::Ref(value_ref) => {
 
                                    let subject = self.store.read_ref(value_ref);
 
                                    let subject_heap_pos = subject.as_struct();
 

	
 
                                    (None, Value::Ref(ValueId::Heap(subject_heap_pos, field_idx)))
 
                                },
 
                                _ => {
 
                                    let subject_heap_pos = subject.as_struct();
 
                                    let subject_indexed = Value::Ref(ValueId::Heap(subject_heap_pos, field_idx));
 
                                    (Some(subject_heap_pos), self.store.clone_value(subject_indexed))
 
                                },
 
                            };
 

	
 
                            cur_frame.expr_values.push_back(value_to_push);
 
                            self.store.drop_value(deallocate_heap_pos);
 
                        },
 
                        Expression::Literal(expr) => {
 
                            let value = match &expr.value {
 
                                Literal::Null => Value::Null,
 
                                Literal::True => Value::Bool(true),
 
                                Literal::False => Value::Bool(false),
 
                                Literal::Character(lit_value) => Value::Char(*lit_value),
 
                                Literal::String(lit_value) => {
 
                                    let heap_pos = self.store.alloc_heap();
 
                                    let values = &mut self.store.heap_regions[heap_pos as usize].values;
 
                                    let value = lit_value.as_str();
 
                                    debug_assert!(values.is_empty());
 
                                    values.reserve(value.len());
 
                                    for character in value.as_bytes() {
 
                                        debug_assert!(character.is_ascii());
 
                                        values.push(Value::Char(*character as char));
 
                                    }
 
                                    Value::String(heap_pos)
 
                                }
 
                                Literal::Integer(lit_value) => {
 
                                    use ConcreteTypePart as CTP;
 
                                    let def_types = types.get_procedure_expression_data(&cur_frame.definition, cur_frame.monomorph_idx);
 
                                    let concrete_type = &def_types.expr_data[expr.unique_id_in_definition as usize].expr_type;
 

	
 
                                    debug_assert_eq!(concrete_type.parts.len(), 1);
 
                                    match concrete_type.parts[0] {
 
                                        CTP::UInt8  => Value::UInt8(lit_value.unsigned_value as u8),
 
                                        CTP::UInt16 => Value::UInt16(lit_value.unsigned_value as u16),
 
                                        CTP::UInt32 => Value::UInt32(lit_value.unsigned_value as u32),
 
                                        CTP::UInt64 => Value::UInt64(lit_value.unsigned_value as u64),
 
                                        CTP::SInt8  => Value::SInt8(lit_value.unsigned_value as i8),
 
                                        CTP::SInt16 => Value::SInt16(lit_value.unsigned_value as i16),
 
                                        CTP::SInt32 => Value::SInt32(lit_value.unsigned_value as i32),
 
                                        CTP::SInt64 => Value::SInt64(lit_value.unsigned_value as i64),
 
                                        _ => unreachable!("got concrete type {:?} for integer literal at expr {:?}", concrete_type, expr_id),
 
                                    }
 
                                }
 
                                Literal::Struct(lit_value) => {
 
                                    let heap_pos = transfer_expression_values_front_into_heap(
 
                                        cur_frame, &mut self.store, lit_value.fields.len()
 
                                    );
 
                                    Value::Struct(heap_pos)
 
                                }
 
                                Literal::Enum(lit_value) => {
 
                                    Value::Enum(lit_value.variant_idx as i64)
 
                                }
 
                                Literal::Union(lit_value) => {
 
                                    let heap_pos = transfer_expression_values_front_into_heap(
 
                                        cur_frame, &mut self.store, lit_value.values.len()
 
                                    );
 
                                    Value::Union(lit_value.variant_idx as i64, heap_pos)
 
                                }
 
                                Literal::Array(lit_value) => {
 
                                    let heap_pos = transfer_expression_values_front_into_heap(
 
                                        cur_frame, &mut self.store, lit_value.len()
 
                                    );
 
                                    Value::Array(heap_pos)
 
                                }
 
                            };
 

	
 
                            cur_frame.expr_values.push_back(value);
 
                        },
 
                        Expression::Cast(expr) => {
 
                            let mono_data = types.get_procedure_expression_data(&cur_frame.definition, cur_frame.monomorph_idx);
 
                            let output_type = &mono_data.expr_data[expr.unique_id_in_definition as usize].expr_type;
 

	
 
                            // Typechecking reduced this to two cases: either we
 
                            // have casting noop (same types), or we're casting
 
                            // between integer/bool/char types.
 
                            let subject = cur_frame.expr_values.pop_back().unwrap();
 
                            match apply_casting(&mut self.store, output_type, &subject) {
 
                                Ok(value) => cur_frame.expr_values.push_back(value),
 
                                Err(msg) => {
 
                                    return Err(EvalError::new_error_at_expr(self, modules, heap, expr.this.upcast(), msg));
 
                                }
 
                            }
 

	
 
                            self.store.drop_value(subject.get_heap_pos());
 
                        }
 
                        Expression::Call(expr) => {
 
                            // If we're dealing with a builtin we don't do any
 
                            // fancy shenanigans at all, just push the result.
 
                            match expr.method {
 
                                Method::Get => {
 
                                    let value = cur_frame.expr_values.pop_front().unwrap();
 
                                    let value = self.store.maybe_read_ref(&value).clone();
 

	
 
                                    match ctx.get(value.clone(), &mut self.store) {
 
                                        Some(result) => {
 
                                            cur_frame.expr_values.push_back(result)
 
                                        },
 
                                        None => {
 
                                            cur_frame.expr_values.push_front(value.clone());
 
                                            cur_frame.expr_stack.push_back(ExprInstruction::EvalExpr(expr_id));
 
                                            return Ok(EvalContinuation::BlockGet(value));
 
                                        }
 
                                    }
 
                                },
 
                                Method::Put => {
 
                                    let port_value = cur_frame.expr_values.pop_front().unwrap();
 
                                    let deref_port_value = self.store.maybe_read_ref(&port_value).clone();
 
                                    let msg_value = cur_frame.expr_values.pop_front().unwrap();
 
                                    let deref_msg_value = self.store.maybe_read_ref(&msg_value).clone();
 

	
 
                                    if ctx.did_put(deref_port_value.clone()) {
 
                                        // We're fine, deallocate in case the expression value stack
 
                                        // held an owned value
 
                                        self.store.drop_value(msg_value.get_heap_pos());
 
                                    } else {
 
                                        cur_frame.expr_values.push_front(msg_value);
 
                                        cur_frame.expr_values.push_front(port_value);
 
                                        cur_frame.expr_stack.push_back(ExprInstruction::EvalExpr(expr_id));
 
                                        return Ok(EvalContinuation::Put(deref_port_value, deref_msg_value));
 
                                    }
 
                                },
 
                                Method::Fires => {
 
                                    let port_value = cur_frame.expr_values.pop_front().unwrap();
 
                                    let port_value_deref = self.store.maybe_read_ref(&port_value).clone();
 
                                    match ctx.fires(port_value_deref.clone()) {
 
                                        None => {
 
                                            cur_frame.expr_values.push_front(port_value);
 
                                            cur_frame.expr_stack.push_back(ExprInstruction::EvalExpr(expr_id));
 
                                            return Ok(EvalContinuation::BlockFires(port_value_deref));
 
                                        },
 
                                        Some(value) => {
 
                                            cur_frame.expr_values.push_back(value);
 
                                        }
 
                                    }
 
                                },
 
                                Method::Create => {
 
                                    let length_value = cur_frame.expr_values.pop_front().unwrap();
 
                                    let length_value = self.store.maybe_read_ref(&length_value);
 
                                    let length = if length_value.is_signed_integer() {
 
                                        let length_value = length_value.as_signed_integer();
 
                                        if length_value < 0 {
 
                                            return Err(EvalError::new_error_at_expr(
 
                                                self, modules, heap, expr_id,
 
                                                format!("got length '{}', can only create a message with a non-negative length", length_value)
 
                                            ));
 
                                        }
 

	
 
                                        length_value as u64
 
                                    } else {
 
                                        debug_assert!(length_value.is_unsigned_integer());
 
                                        length_value.as_unsigned_integer()
 
                                    };
 

	
 
                                    let heap_pos = self.store.alloc_heap();
 
                                    let values = &mut self.store.heap_regions[heap_pos as usize].values;
 
                                    debug_assert!(values.is_empty());
 
                                    values.resize(length as usize, Value::UInt8(0));
 
                                    cur_frame.expr_values.push_back(Value::Message(heap_pos));
 
                                },
 
                                Method::Length => {
 
                                    let value = cur_frame.expr_values.pop_front().unwrap();
 
                                    let value_heap_pos = value.get_heap_pos();
 
                                    let value = self.store.maybe_read_ref(&value);
 

	
 
                                    let heap_pos = match value {
 
                                        Value::Array(pos) => *pos,
 
                                        Value::String(pos) => *pos,
 
                                        _ => unreachable!("length(...) on {:?}", value),
 
                                    };
 

	
 
                                    let len = self.store.heap_regions[heap_pos as usize].values.len();
 

	
 
                                    // TODO: @PtrInt
 
                                    cur_frame.expr_values.push_back(Value::UInt32(len as u32));
 
                                    self.store.drop_value(value_heap_pos);
 
                                },
 
                                Method::Assert => {
 
                                    let value = cur_frame.expr_values.pop_front().unwrap();
 
                                    let value = self.store.maybe_read_ref(&value).clone();
 
                                    if !value.as_bool() {
 
                                        return Ok(EvalContinuation::Inconsistent)
 
                                    }
 
                                },
 
                                Method::UserComponent => {
 
                                    // This is actually handled by the evaluation
 
                                    // of the statement.
 
                                    debug_assert_eq!(heap[expr.definition].parameters().len(), cur_frame.expr_values.len());
 
                                    debug_assert_eq!(heap[cur_frame.position].as_new().expression, expr.this)
 
                                },
 
                                Method::UserFunction => {
 
                                    // Push a new frame. Note that all expressions have
 
                                    // been pushed to the front, so they're in the order
 
                                    // of the definition.
 
                                    let num_args = expr.arguments.len();
 

	
 
                                    // Determine stack boundaries
 
                                    let cur_stack_boundary = self.store.cur_stack_boundary;
 
                                    let new_stack_boundary = self.store.stack.len();
 

	
 
                                    // Push new boundary and function arguments for new frame
 
                                    self.store.stack.push(Value::PrevStackBoundary(cur_stack_boundary as isize));
 
                                    for _ in 0..num_args {
 
                                        let argument = self.store.read_take_ownership(cur_frame.expr_values.pop_front().unwrap());
 
                                        self.store.stack.push(argument);
 
                                    }
 

	
 
                                    // Determine the monomorph index of the function we're calling
 
                                    let mono_data = types.get_procedure_expression_data(&cur_frame.definition, cur_frame.monomorph_idx);
 
                                    let call_data = &mono_data.expr_data[expr.unique_id_in_definition as usize];
 

	
 
                                    // Push the new frame and reserve its stack size
 
                                    let new_frame = Frame::new(heap, expr.definition, call_data.field_or_monomorph_idx);
 
                                    let new_stack_size = new_frame.max_stack_size;
 
                                    self.frames.push(new_frame);
 
                                    self.store.cur_stack_boundary = new_stack_boundary;
 
                                    self.store.reserve_stack(new_stack_size);
 

	
 
                                    // To simplify the logic a little bit we will now
 
                                    // return and ask our caller to call us again
 
                                    return Ok(EvalContinuation::Stepping);
 
                                },
 
                            }
 
                        },
 
                        Expression::Variable(expr) => {
 
                            let variable = &heap[expr.declaration.unwrap()];
 
                            let ref_value = if expr.used_as_binding_target {
 
                                Value::Binding(variable.unique_id_in_scope as StackPos)
 
                            } else {
 
                                Value::Ref(ValueId::Stack(variable.unique_id_in_scope as StackPos))
 
                            };
 
                            cur_frame.expr_values.push_back(ref_value);
 
                        }
 
                    }
 
                }
 
            }
 
        }
 

	
 
        debug_log!("Frame [{:?}] at {:?}", cur_frame.definition, cur_frame.position);
 
        if debug_enabled!() {
 
            debug_log!("Expression value stack (size = {}):", cur_frame.expr_values.len());
 
            for (_stack_idx, _stack_val) in cur_frame.expr_values.iter().enumerate() {
 
                debug_log!("  [{:03}] {:?}", _stack_idx, _stack_val);
 
            }
 

	
 
            debug_log!("Stack (size = {}):", self.store.stack.len());
 
            for (_stack_idx, _stack_val) in self.store.stack.iter().enumerate() {
 
                debug_log!("  [{:03}] {:?}", _stack_idx, _stack_val);
 
            }
 

	
 
            debug_log!("Heap:");
 
            for (_heap_idx, _heap_region) in self.store.heap_regions.iter().enumerate() {
 
                let _is_free = self.store.free_regions.iter().any(|idx| *idx as usize == _heap_idx);
 
                debug_log!("  [{:03}] in_use: {}, len: {}, vals: {:?}", _heap_idx, !_is_free, heap_region.values.len(), &_heap_region.values);
 
                debug_log!("  [{:03}] in_use: {}, len: {}, vals: {:?}", _heap_idx, !_is_free, _heap_region.values.len(), &_heap_region.values);
 
            }
 
        }
 
        // No (more) expressions to evaluate. So evaluate statement (that may
 
        // depend on the result on the last evaluated expression(s))
 
        let stmt = &heap[cur_frame.position];
 
        let return_value = match stmt {
 
            Statement::Block(stmt) => {
 
                debug_assert!(stmt.statements.is_empty() || stmt.next == stmt.statements[0]);
 
                cur_frame.position = stmt.next;
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::EndBlock(stmt) => {
 
                let block = &heap[stmt.start_block];
 
                self.store.clear_stack(block.first_unique_id_in_scope as usize);
 
                cur_frame.position = stmt.next;
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::Local(stmt) => {
 
                match stmt {
 
                    LocalStatement::Memory(stmt) => {
 
                        let variable = &heap[stmt.variable];
 
                        self.store.write(ValueId::Stack(variable.unique_id_in_scope as u32), Value::Unassigned);
 

	
 
                        cur_frame.position = stmt.next;
 
                    },
 
                    LocalStatement::Channel(stmt) => {
 
                        let [from_value, to_value] = ctx.new_channel();
 
                        self.store.write(ValueId::Stack(heap[stmt.from].unique_id_in_scope as u32), from_value);
 
                        self.store.write(ValueId::Stack(heap[stmt.to].unique_id_in_scope as u32), to_value);
 

	
 
                        cur_frame.position = stmt.next;
 
                    }
 
                }
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::Labeled(stmt) => {
 
                cur_frame.position = stmt.body;
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::If(stmt) => {
 
                debug_assert_eq!(cur_frame.expr_values.len(), 1, "expected one expr value for if statement");
 
                let test_value = cur_frame.expr_values.pop_back().unwrap();
 
                let test_value = self.store.maybe_read_ref(&test_value).as_bool();
 
                if test_value {
 
                    cur_frame.position = stmt.true_body.upcast();
 
                } else if let Some(false_body) = stmt.false_body {
 
                    cur_frame.position = false_body.upcast();
 
                } else {
 
                    // Not true, and no false body
 
                    cur_frame.position = stmt.end_if.upcast();
 
                }
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::EndIf(stmt) => {
 
                cur_frame.position = stmt.next;
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::While(stmt) => {
 
                debug_assert_eq!(cur_frame.expr_values.len(), 1, "expected one expr value for while statement");
 
                let test_value = cur_frame.expr_values.pop_back().unwrap();
 
                let test_value = self.store.maybe_read_ref(&test_value).as_bool();
 
                if test_value {
 
                    cur_frame.position = stmt.body.upcast();
 
                } else {
 
                    cur_frame.position = stmt.end_while.upcast();
 
                }
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::EndWhile(stmt) => {
 
                cur_frame.position = stmt.next;
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::Break(stmt) => {
 
                cur_frame.position = stmt.target.unwrap().upcast();
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::Continue(stmt) => {
 
                cur_frame.position = stmt.target.unwrap().upcast();
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::Synchronous(stmt) => {
 
                cur_frame.position = stmt.body.upcast();
 

	
 
                Ok(EvalContinuation::SyncBlockStart)
 
            },
 
            Statement::EndSynchronous(stmt) => {
 
                cur_frame.position = stmt.next;
 

	
 
                Ok(EvalContinuation::SyncBlockEnd)
 
            },
 
            Statement::Return(_stmt) => {
 
                debug_assert!(heap[cur_frame.definition].is_function());
 
                debug_assert_eq!(cur_frame.expr_values.len(), 1, "expected one expr value for return statement");
 

	
 
                // The preceding frame has executed a call, so is expecting the
 
                // return expression on its expression value stack. Note that
 
                // we may be returning a reference to something on our stack,
 
                // so we need to read that value and clone it.
 
                let return_value = cur_frame.expr_values.pop_back().unwrap();
 
                let return_value = match return_value {
 
                    Value::Ref(value_id) => self.store.read_copy(value_id),
 
                    _ => return_value,
 
                };
 

	
 
                // Pre-emptively pop our stack frame
 
                self.frames.pop();
 

	
 
                // Clean up our section of the stack
 
                self.store.clear_stack(0);
 
                self.store.stack.truncate(self.store.cur_stack_boundary + 1);
 
                let prev_stack_idx = self.store.stack.pop().unwrap().as_stack_boundary();
 

	
 
                // TODO: Temporary hack for testing, remove at some point
 
                if self.frames.is_empty() {
 
                    debug_assert!(prev_stack_idx == -1);
 
                    debug_assert!(self.store.stack.len() == 0);
 
                    self.store.stack.push(return_value);
 
                    return Ok(EvalContinuation::Terminal);
 
                }
 

	
 
                debug_assert!(prev_stack_idx >= 0);
 
                // Return to original state of stack frame
 
                self.store.cur_stack_boundary = prev_stack_idx as usize;
 
                let cur_frame = self.frames.last_mut().unwrap();
 
                cur_frame.expr_values.push_back(return_value);
 

	
 
                // We just returned to the previous frame, which might be in
 
                // the middle of evaluating expressions for a particular
 
                // statement. So we don't want to enter the code below.
 
                return Ok(EvalContinuation::Stepping);
 
            },
 
            Statement::Goto(stmt) => {
 
                cur_frame.position = stmt.target.unwrap().upcast();
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::New(stmt) => {
 
                let call_expr = &heap[stmt.expression];
 
                debug_assert!(heap[call_expr.definition].is_component());
 
                debug_assert_eq!(
 
                    cur_frame.expr_values.len(), heap[call_expr.definition].parameters().len(),
 
                    "mismatch in expr stack size and number of arguments for new statement"
 
                );
 

	
 
                let mono_data = types.get_procedure_expression_data(&cur_frame.definition, cur_frame.monomorph_idx);
 
                let expr_data = &mono_data.expr_data[call_expr.unique_id_in_definition as usize];
 

	
 
                // Note that due to expression value evaluation they exist in
 
                // reverse order on the stack.
 
                // TODO: Revise this code, keep it as is to be compatible with current runtime
 
                let mut args = Vec::new();
 
                while let Some(value) = cur_frame.expr_values.pop_front() {
 
                    args.push(value);
 
                }
 

	
 
                // Construct argument group, thereby copying heap regions
 
                let argument_group = ValueGroup::from_store(&self.store, &args);
 

	
 
                // Clear any heap regions
 
                for arg in &args {
 
                    self.store.drop_value(arg.get_heap_pos());
 
                }
 

	
 
                cur_frame.position = stmt.next;
 

	
 
                Ok(EvalContinuation::NewComponent(call_expr.definition, expr_data.field_or_monomorph_idx, argument_group))
 
            },
 
            Statement::Expression(stmt) => {
 
                // The expression has just been completely evaluated. Some
 
                // values might have remained on the expression value stack.
 
                // cur_frame.expr_values.clear(); PROPER CLEARING
 
                cur_frame.position = stmt.next;
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
        };
 

	
 
        assert!(
 
            cur_frame.expr_values.is_empty(),
 
            "This is a debugging assertion that will fail if you perform expressions without \
 
            assigning to anything. This should be completely valid, and this assertion should be \
 
            replaced by something that clears the expression values if needed, but I'll keep this \
 
            in for now for debugging purposes."
 
        );
 

	
 
        // If the next statement requires evaluating expressions then we push
 
        // these onto the expression stack. This way we will evaluate this
 
        // stack in the next loop, then evaluate the statement using the result
 
        // from the expression evaluation.
 
        if !cur_frame.position.is_invalid() {
 
            let stmt = &heap[cur_frame.position];
 

	
 
            match stmt {
 
                Statement::If(stmt) => cur_frame.prepare_single_expression(heap, stmt.test),
 
                Statement::While(stmt) => cur_frame.prepare_single_expression(heap, stmt.test),
 
                Statement::Return(stmt) => {
 
                    debug_assert_eq!(stmt.expressions.len(), 1); // TODO: @ReturnValues
 
                    cur_frame.prepare_single_expression(heap, stmt.expressions[0]);
 
                },
 
                Statement::New(stmt) => {
 
                    // Note that we will end up not evaluating the call itself.
 
                    // Rather we will evaluate its expressions and then
 
                    // instantiate the component upon reaching the "new" stmt.
 
                    let call_expr = &heap[stmt.expression];
 
                    cur_frame.prepare_multiple_expressions(heap, &call_expr.arguments);
 
                },
 
                Statement::Expression(stmt) => {
 
                    cur_frame.prepare_single_expression(heap, stmt.expression);
 
                }
 
                _ => {},
 
            }
 
        }
 

	
 
        return_value
 
    }
 
}
 
\ No newline at end of file
src/protocol/eval/value.rs
Show inline comments
 

	
 
use super::store::*;
 
use crate::PortId;
 
use crate::protocol::ast::{
 
    AssignmentOperator,
 
    BinaryOperator,
 
    UnaryOperator,
 
    ConcreteType,
 
    ConcreteTypePart,
 
};
 
use crate::protocol::parser::token_parsing::*;
 

	
 
pub type StackPos = u32;
 
pub type HeapPos = u32;
 

	
 
#[derive(Debug, Copy, Clone)]
 
pub enum ValueId {
 
    Stack(StackPos), // place on stack
 
    Heap(HeapPos, u32), // allocated region + values within that region
 
}
 

	
 
/// Represents a value stored on the stack or on the heap. Some values contain
 
/// a `HeapPos`, implying that they're stored in the store's `Heap`. Clearing
 
/// a `Value` with a `HeapPos` from a stack must also clear the associated
 
/// region from the `Heap`.
 
#[derive(Debug, Clone)]
 
pub enum Value {
 
    // Special types, never encountered during evaluation if the compiler works correctly
 
    Unassigned,                 // Marker when variables are first declared, immediately followed by assignment
 
    PrevStackBoundary(isize),   // Marker for stack frame beginning, so we can pop stack values
 
    Ref(ValueId),               // Reference to a value, used by expressions producing references
 
    Binding(StackPos),          // Reference to a binding variable (reserved on the stack)
 
    // Builtin types
 
    Input(PortId),
 
    Output(PortId),
 
    Message(HeapPos),
 
    Null,
 
    Bool(bool),
 
    Char(char),
 
    String(HeapPos),
 
    UInt8(u8),
 
    UInt16(u16),
 
    UInt32(u32),
 
    UInt64(u64),
 
    SInt8(i8),
 
    SInt16(i16),
 
    SInt32(i32),
 
    SInt64(i64),
 
    Array(HeapPos),
 
    // Instances of user-defined types
 
    Enum(i64),
 
    Union(i64, HeapPos),
 
    Struct(HeapPos),
 
}
 

	
 
macro_rules! impl_union_unpack_as_value {
 
    ($func_name:ident, $variant_name:path, $return_type:ty) => {
 
        impl Value {
 
            pub(crate) fn $func_name(&self) -> $return_type {
 
                match self {
 
                    $variant_name(v) => *v,
 
                    _ => panic!(concat!("called ", stringify!($func_name()), " on {:?}"), self),
 
                }
 
            }
 
        }
 
    }
 
}
 

	
 
impl_union_unpack_as_value!(as_stack_boundary, Value::PrevStackBoundary, isize);
 
impl_union_unpack_as_value!(as_ref,     Value::Ref,     ValueId);
 
impl_union_unpack_as_value!(as_input,   Value::Input,   PortId);
 
impl_union_unpack_as_value!(as_output,  Value::Output,  PortId);
 
impl_union_unpack_as_value!(as_message, Value::Message, HeapPos);
 
impl_union_unpack_as_value!(as_bool,    Value::Bool,    bool);
 
impl_union_unpack_as_value!(as_char,    Value::Char,    char);
 
impl_union_unpack_as_value!(as_string,  Value::String,  HeapPos);
 
impl_union_unpack_as_value!(as_uint8,   Value::UInt8,   u8);
 
impl_union_unpack_as_value!(as_uint16,  Value::UInt16,  u16);
 
impl_union_unpack_as_value!(as_uint32,  Value::UInt32,  u32);
 
impl_union_unpack_as_value!(as_uint64,  Value::UInt64,  u64);
 
impl_union_unpack_as_value!(as_sint8,   Value::SInt8,   i8);
 
impl_union_unpack_as_value!(as_sint16,  Value::SInt16,  i16);
 
impl_union_unpack_as_value!(as_sint32,  Value::SInt32,  i32);
 
impl_union_unpack_as_value!(as_sint64,  Value::SInt64,  i64);
 
impl_union_unpack_as_value!(as_array,   Value::Array,   HeapPos);
 
impl_union_unpack_as_value!(as_enum,    Value::Enum,    i64);
 
impl_union_unpack_as_value!(as_struct,  Value::Struct,  HeapPos);
 

	
 
impl Value {
 
    pub(crate) fn as_union(&self) -> (i64, HeapPos) {
 
        match self {
 
            Value::Union(tag, v) => (*tag, *v),
 
            _ => panic!("called as_union on {:?}", self),
 
        }
 
    }
 

	
 
    pub(crate) fn is_integer(&self) -> bool {
 
        match self {
 
            Value::UInt8(_) | Value::UInt16(_) | Value::UInt32(_) | Value::UInt64(_) |
 
            Value::SInt8(_) | Value::SInt16(_) | Value::SInt32(_) | Value::SInt64(_) => true,
 
            _ => false
 
        }
 
    }
 

	
 
    pub(crate) fn is_unsigned_integer(&self) -> bool {
 
        match self {
 
            Value::UInt8(_) | Value::UInt16(_) | Value::UInt32(_) | Value::UInt64(_) => true,
 
            _ => false
 
        }
 
    }
 

	
 
    pub(crate) fn is_signed_integer(&self) -> bool {
 
        match self {
 
            Value::SInt8(_) | Value::SInt16(_) | Value::SInt32(_) | Value::SInt64(_) => true,
 
            _ => false
 
        }
 
    }
 

	
 
    pub(crate) fn as_unsigned_integer(&self) -> u64 {
 
        match self {
 
            Value::UInt8(v)  => *v as u64,
 
            Value::UInt16(v) => *v as u64,
 
            Value::UInt32(v) => *v as u64,
 
            Value::UInt64(v) => *v as u64,
 
            _ => unreachable!("called as_unsigned_integer on {:?}", self),
 
        }
 
    }
 

	
 
    pub(crate) fn as_signed_integer(&self) -> i64 {
 
        match self {
 
            Value::SInt8(v)  => *v as i64,
 
            Value::SInt16(v) => *v as i64,
 
            Value::SInt32(v) => *v as i64,
 
            Value::SInt64(v) => *v as i64,
 
            _ => unreachable!("called as_signed_integer on {:?}", self)
 
        }
 
    }
 

	
 
    /// Returns the heap position associated with the value. If the value
 
    /// doesn't store anything in the heap then we return `None`.
 
    pub(crate) fn get_heap_pos(&self) -> Option<HeapPos> {
 
        match self {
 
            Value::Message(v) => Some(*v),
 
            Value::Array(v) => Some(*v),
 
            Value::Union(_, v) => Some(*v),
 
            Value::Struct(v) => Some(*v),
 
            _ => None
 
        }
 
    }
 
}
 

	
 
/// When providing arguments to a new component, or when transferring values
 
/// from one component's store to a newly instantiated component, one has to
 
/// transfer stack and heap values. This `ValueGroup` represents such a
 
/// temporary group of values with potential heap allocations.
 
///
 
/// Constructing such a ValueGroup manually requires some extra care to make
 
/// sure all elements of `values` point to valid elements of `regions`.
 
///
 
/// Again: this is a temporary thing, hopefully removed once we move to a
 
/// bytecode interpreter.
 
pub struct ValueGroup {
 
    pub(crate) values: Vec<Value>,
 
    pub(crate) regions: Vec<Vec<Value>>
 
}
 

	
 
impl ValueGroup {
 
    pub(crate) fn new_stack(values: Vec<Value>) -> Self {
 
        debug_assert!(values.iter().all(|v| v.get_heap_pos().is_none()));
 
        Self{
 
            values,
 
            regions: Vec::new(),
 
        }
 
    }
 
    pub(crate) fn from_store(store: &Store, values: &[Value]) -> Self {
 
        let mut group = ValueGroup{
 
            values: Vec::with_capacity(values.len()),
 
            regions: Vec::with_capacity(values.len()), // estimation
 
        };
 

	
 
        for value in values {
 
            let transferred = group.retrieve_value(value, store);
 
            group.values.push(transferred);
 
        }
 

	
 
        group
 
    }
 

	
 
    /// Transfers a provided value from a store into a local value with its
 
    /// heap allocations (if any) stored in the ValueGroup. Calling this
 
    /// function will not store the returned value in the `values` member.
 
    fn retrieve_value(&mut self, value: &Value, from_store: &Store) -> Value {
 
        let value = from_store.maybe_read_ref(value);
 
        if let Some(heap_pos) = value.get_heap_pos() {
 
            // Value points to a heap allocation, so transfer the heap values
 
            // internally.
 
            let from_region = &from_store.heap_regions[heap_pos as usize].values;
 
            let mut new_region = Vec::with_capacity(from_region.len());
 
            for value in from_region {
 
                let transferred = self.retrieve_value(value, from_store);
 
                new_region.push(transferred);
 
            }
 

	
 
            // Region is constructed, store internally and return the new value.
 
            let new_region_idx = self.regions.len() as HeapPos;
 
            self.regions.push(new_region);
 

	
 
            return match value {
 
                Value::Message(_)    => Value::Message(new_region_idx),
 
                Value::String(_)     => Value::String(new_region_idx),
 
                Value::Array(_)      => Value::Array(new_region_idx),
 
                Value::Union(tag, _) => Value::Union(*tag, new_region_idx),
 
                Value::Struct(_)     => Value::Struct(new_region_idx),
 
                _ => unreachable!(),
 
            };
 
        } else {
 
            return value.clone();
 
        }
 
    }
 

	
 
    /// Transfers the heap values and the stack values into the store. Stack
 
    /// values are pushed onto the Store's stack in the order in which they
 
    /// appear in the value group.
 
    pub(crate) fn into_store(self, store: &mut Store) {
 
        for value in &self.values {
 
            let transferred = self.provide_value(value, store);
 
            store.stack.push(transferred);
 
        }
 
    }
 

	
 
    fn provide_value(&self, value: &Value, to_store: &mut Store) -> Value {
 
        if let Some(from_heap_pos) = value.get_heap_pos() {
 
            let from_heap_pos = from_heap_pos as usize;
 
            let to_heap_pos = to_store.alloc_heap();
 
            let to_heap_pos_usize = to_heap_pos as usize;
 
            to_store.heap_regions[to_heap_pos_usize].values.reserve(self.regions[from_heap_pos].len());
 

	
 
            for value in &self.regions[from_heap_pos as usize] {
 
                let transferred = self.provide_value(value, to_store);
 
                to_store.heap_regions[to_heap_pos_usize].values.push(transferred);
 
            }
 

	
 
            return match value {
 
                Value::Message(_)    => Value::Message(to_heap_pos),
 
                Value::String(_)     => Value::String(to_heap_pos),
 
                Value::Array(_)      => Value::Array(to_heap_pos),
 
                Value::Union(tag, _) => Value::Union(*tag, to_heap_pos),
 
                Value::Struct(_)     => Value::Struct(to_heap_pos),
 
                _ => unreachable!(),
 
            };
 
        } else {
 
            return value.clone();
 
        }
 
    }
 
}
 

	
 
impl Default for ValueGroup {
 
    /// Returns an empty ValueGroup
 
    fn default() -> Self {
 
        Self { values: Vec::new(), regions: Vec::new() }
 
    }
 
}
 

	
 
enum ValueKind { Message, String, Array }
 

	
 
pub(crate) fn apply_assignment_operator(store: &mut Store, lhs: ValueId, op: AssignmentOperator, rhs: Value) {
 
    use AssignmentOperator as AO;
 

	
 
    macro_rules! apply_int_op {
 
        ($lhs:ident, $assignment_tokens:tt, $operator:ident, $rhs:ident) => {
 
            match $lhs {
 
                Value::UInt8(v)  => { *v $assignment_tokens $rhs.as_uint8();  },
 
                Value::UInt16(v) => { *v $assignment_tokens $rhs.as_uint16(); },
 
                Value::UInt32(v) => { *v $assignment_tokens $rhs.as_uint32(); },
 
                Value::UInt64(v) => { *v $assignment_tokens $rhs.as_uint64(); },
 
                Value::SInt8(v)  => { *v $assignment_tokens $rhs.as_sint8();  },
 
                Value::SInt16(v) => { *v $assignment_tokens $rhs.as_sint16(); },
 
                Value::SInt32(v) => { *v $assignment_tokens $rhs.as_sint32(); },
 
                Value::SInt64(v) => { *v $assignment_tokens $rhs.as_sint64(); },
 
                _ => unreachable!("apply_assignment_operator {:?} on lhs {:?} and rhs {:?}", $operator, $lhs, $rhs),
 
            }
 
        }
 
    }
 

	
 
    // let rhs = store.maybe_read_ref(&rhs).clone(); // we don't own this thing, so don't drop it
 
    let lhs = store.read_mut_ref(lhs);
 

	
 
    let mut to_dealloc = None;
 
    match op {
 
        AO::Set => {
 
            match lhs {
 
                Value::Unassigned => { *lhs = rhs; },
 
                Value::Input(v)  => { *v = rhs.as_input(); },
 
                Value::Output(v) => { *v = rhs.as_output(); },
 
                Value::Message(v)  => { to_dealloc = Some(*v); *v = rhs.as_message(); },
 
                Value::Bool(v)    => { *v = rhs.as_bool(); },
 
                Value::Char(v) => { *v = rhs.as_char(); },
 
                Value::String(v) => { *v = rhs.as_string().clone(); },
 
                Value::UInt8(v) => { *v = rhs.as_uint8(); },
 
                Value::UInt16(v) => { *v = rhs.as_uint16(); },
 
                Value::UInt32(v) => { *v = rhs.as_uint32(); },
 
                Value::UInt64(v) => { *v = rhs.as_uint64(); },
 
                Value::SInt8(v) => { *v = rhs.as_sint8(); },
 
                Value::SInt16(v) => { *v = rhs.as_sint16(); },
 
                Value::SInt32(v) => { *v = rhs.as_sint32(); },
 
                Value::SInt64(v) => { *v = rhs.as_sint64(); },
 
                Value::Array(v) => { to_dealloc = Some(*v); *v = rhs.as_array(); },
 
                Value::Enum(v) => { *v = rhs.as_enum(); },
 
                Value::Union(lhs_tag, lhs_heap_pos) => {
 
                    to_dealloc = Some(*lhs_heap_pos);
 
                    let (rhs_tag, rhs_heap_pos) = rhs.as_union();
 
                    *lhs_tag = rhs_tag;
 
                    *lhs_heap_pos = rhs_heap_pos;
 
                }
 
                Value::Struct(v) => { to_dealloc = Some(*v); *v = rhs.as_struct(); },
 
                _ => unreachable!("apply_assignment_operator {:?} on lhs {:?} and rhs {:?}", op, lhs, rhs),
 
            }
 
        },
 
        AO::Concatenated => {
 
            let lhs_heap_pos = lhs.get_heap_pos().unwrap() as usize;
 
            let rhs_heap_pos = rhs.get_heap_pos().unwrap() as usize;
 

	
 
            // To prevent borrowing crap, swap out heap region with a temp empty array
 
            let mut total = Vec::new();
 
            std::mem::swap(&mut total, &mut store.heap_regions[lhs_heap_pos].values);
 

	
 
            // Push everything onto the swapped vector
 
            let rhs_len = store.heap_regions[rhs_heap_pos].values.len();
 
            total.reserve(rhs_len);
 
            for value_idx in 0..rhs_len {
 
                total.push(store.clone_value(store.heap_regions[rhs_heap_pos].values[value_idx].clone()));
 
            }
 

	
 
            // Swap back in place
 
            std::mem::swap(&mut total, &mut store.heap_regions[lhs_heap_pos].values);
 

	
 
            // We took ownership of the RHS, but we copied it into the LHS, so
 
            // different form assignment we need to drop the RHS heap pos.
 
            to_dealloc = Some(rhs_heap_pos as u32);
 
        },
 
        AO::Multiplied =>   { apply_int_op!(lhs, *=,  op, rhs) },
 
        AO::Divided =>      { apply_int_op!(lhs, /=,  op, rhs) },
 
        AO::Remained =>     { apply_int_op!(lhs, %=,  op, rhs) },
 
        AO::Added =>        { apply_int_op!(lhs, +=,  op, rhs) },
 
        AO::Subtracted =>   { apply_int_op!(lhs, -=,  op, rhs) },
 
        AO::ShiftedLeft =>  { apply_int_op!(lhs, <<=, op, rhs) },
 
        AO::ShiftedRight => { apply_int_op!(lhs, >>=, op, rhs) },
 
        AO::BitwiseAnded => { apply_int_op!(lhs, &=,  op, rhs) },
 
        AO::BitwiseXored => { apply_int_op!(lhs, ^=,  op, rhs) },
 
        AO::BitwiseOred =>  { apply_int_op!(lhs, |=,  op, rhs) },
 
    }
 

	
 
    if let Some(heap_pos) = to_dealloc {
 
        store.drop_heap_pos(heap_pos);
 
    }
 
}
 

	
 
pub(crate) fn apply_binary_operator(store: &mut Store, lhs: &Value, op: BinaryOperator, rhs: &Value) -> Value {
 
    use BinaryOperator as BO;
 

	
 
    macro_rules! apply_int_op_and_return_self {
 
        ($lhs:ident, $operator_tokens:tt, $operator:ident, $rhs:ident) => {
 
            return match $lhs {
 
                Value::UInt8(v)  => { Value::UInt8( *v $operator_tokens $rhs.as_uint8() ) },
 
                Value::UInt16(v) => { Value::UInt16(*v $operator_tokens $rhs.as_uint16()) },
 
                Value::UInt32(v) => { Value::UInt32(*v $operator_tokens $rhs.as_uint32()) },
 
                Value::UInt64(v) => { Value::UInt64(*v $operator_tokens $rhs.as_uint64()) },
 
                Value::SInt8(v)  => { Value::SInt8( *v $operator_tokens $rhs.as_sint8() ) },
 
                Value::SInt16(v) => { Value::SInt16(*v $operator_tokens $rhs.as_sint16()) },
 
                Value::SInt32(v) => { Value::SInt32(*v $operator_tokens $rhs.as_sint32()) },
 
                Value::SInt64(v) => { Value::SInt64(*v $operator_tokens $rhs.as_sint64()) },
 
                _ => unreachable!("apply_binary_operator {:?} on lhs {:?} and rhs {:?}", $operator, $lhs, $rhs)
 
            };
 
        }
 
    }
 

	
 
    macro_rules! apply_int_op_and_return_bool {
 
        ($lhs:ident, $operator_tokens:tt, $operator:ident, $rhs:ident) => {
 
            return match $lhs {
 
                Value::UInt8(v)  => { Value::Bool(*v $operator_tokens $rhs.as_uint8() ) },
 
                Value::UInt16(v) => { Value::Bool(*v $operator_tokens $rhs.as_uint16()) },
 
                Value::UInt32(v) => { Value::Bool(*v $operator_tokens $rhs.as_uint32()) },
 
                Value::UInt64(v) => { Value::Bool(*v $operator_tokens $rhs.as_uint64()) },
 
                Value::SInt8(v)  => { Value::Bool(*v $operator_tokens $rhs.as_sint8() ) },
 
                Value::SInt16(v) => { Value::Bool(*v $operator_tokens $rhs.as_sint16()) },
 
                Value::SInt32(v) => { Value::Bool(*v $operator_tokens $rhs.as_sint32()) },
 
                Value::SInt64(v) => { Value::Bool(*v $operator_tokens $rhs.as_sint64()) },
 
                _ => unreachable!("apply_binary_operator {:?} on lhs {:?} and rhs {:?}", $operator, $lhs, $rhs)
 
            };
 
        }
 
    }
 

	
 
    // We need to handle concatenate in a special way because it needs the store
 
    // mutably.
 
    if op == BO::Concatenate {
 
        let target_heap_pos = store.alloc_heap();
 
        let lhs_heap_pos;
 
        let rhs_heap_pos;
 

	
 
        let lhs = store.maybe_read_ref(lhs);
 
        let rhs = store.maybe_read_ref(rhs);
 

	
 
        enum ValueKind { Message, String, Array }
 
        let value_kind;
 

	
 
        match lhs {
 
            Value::Message(lhs_pos) => {
 
                lhs_heap_pos = *lhs_pos;
 
                rhs_heap_pos = rhs.as_message();
 
                value_kind = ValueKind::Message;
 
            },
 
            Value::String(lhs_pos) => {
 
                lhs_heap_pos = *lhs_pos;
 
                rhs_heap_pos = rhs.as_string();
 
                value_kind = ValueKind::String;
 
            },
 
            Value::Array(lhs_pos) => {
 
                lhs_heap_pos = *lhs_pos;
 
                rhs_heap_pos = rhs.as_array();
 
                value_kind = ValueKind::Array;
 
            },
 
            _ => unreachable!("apply_binary_operator {:?} on lhs {:?} and rhs {:?}", op, lhs, rhs)
 
        }
 

	
 
        let lhs_heap_pos = lhs_heap_pos as usize;
 
        let rhs_heap_pos = rhs_heap_pos as usize;
 

	
 
        // TODO: I hate this, but fine...
 
        let mut concatenated = Vec::new();
 
        let lhs_len = store.heap_regions[lhs_heap_pos].values.len();
 
        let rhs_len = store.heap_regions[rhs_heap_pos].values.len();
 
        concatenated.reserve(lhs_len + rhs_len);
 
        for idx in 0..lhs_len {
 
            concatenated.push(store.clone_value(store.heap_regions[lhs_heap_pos].values[idx].clone()));
 
        }
 
        for idx in 0..rhs_len {
 
            concatenated.push(store.clone_value(store.heap_regions[rhs_heap_pos].values[idx].clone()));
 
        }
 

	
 
        store.heap_regions[target_heap_pos as usize].values = concatenated;
 

	
 
        return match value_kind{
 
            ValueKind::Message => Value::Message(target_heap_pos),
 
            ValueKind::String => Value::String(target_heap_pos),
 
            ValueKind::Array => Value::Array(target_heap_pos),
 
        };
 
    }
 

	
 
    // If any of the values are references, retrieve the thing they're referring
 
    // to.
 
    let lhs = store.maybe_read_ref(lhs);
 
    let rhs = store.maybe_read_ref(rhs);
 

	
 
    match op {
 
        BO::Concatenate => unreachable!(),
 
        BO::LogicalOr => {
 
            return Value::Bool(lhs.as_bool() || rhs.as_bool());
 
        },
 
        BO::LogicalAnd => {
 
            return Value::Bool(lhs.as_bool() && rhs.as_bool());
 
        },
 
        BO::BitwiseOr        => { apply_int_op_and_return_self!(lhs, |,  op, rhs); },
 
        BO::BitwiseXor       => { apply_int_op_and_return_self!(lhs, ^,  op, rhs); },
 
        BO::BitwiseAnd       => { apply_int_op_and_return_self!(lhs, &,  op, rhs); },
 
        BO::Equality         => { Value::Bool(apply_equality_operator(store, lhs, rhs)) },
 
        BO::Inequality       => { Value::Bool(apply_inequality_operator(store, lhs, rhs)) },
 
        BO::LessThan         => { apply_int_op_and_return_bool!(lhs, <,  op, rhs); },
 
        BO::GreaterThan      => { apply_int_op_and_return_bool!(lhs, >,  op, rhs); },
 
        BO::LessThanEqual    => { apply_int_op_and_return_bool!(lhs, <=, op, rhs); },
 
        BO::GreaterThanEqual => { apply_int_op_and_return_bool!(lhs, >=, op, rhs); },
 
        BO::ShiftLeft        => { apply_int_op_and_return_self!(lhs, <<, op, rhs); },
 
        BO::ShiftRight       => { apply_int_op_and_return_self!(lhs, >>, op, rhs); },
 
        BO::Add              => { apply_int_op_and_return_self!(lhs, +,  op, rhs); },
 
        BO::Subtract         => { apply_int_op_and_return_self!(lhs, -,  op, rhs); },
 
        BO::Multiply         => { apply_int_op_and_return_self!(lhs, *,  op, rhs); },
 
        BO::Divide           => { apply_int_op_and_return_self!(lhs, /,  op, rhs); },
 
        BO::Remainder        => { apply_int_op_and_return_self!(lhs, %,  op, rhs); }
 
    }
 
}
 

	
 
pub(crate) fn apply_unary_operator(store: &mut Store, op: UnaryOperator, value: &Value) -> Value {
 
    use UnaryOperator as UO;
 

	
 
    macro_rules! apply_int_expr_and_return {
 
        ($value:ident, $apply:tt, $op:ident) => {
 
            return match $value {
 
                Value::UInt8(v)  => Value::UInt8($apply *v),
 
                Value::UInt16(v) => Value::UInt16($apply *v),
 
                Value::UInt32(v) => Value::UInt32($apply *v),
 
                Value::UInt64(v) => Value::UInt64($apply *v),
 
                Value::SInt8(v)  => Value::SInt8($apply *v),
 
                Value::SInt16(v) => Value::SInt16($apply *v),
 
                Value::SInt32(v) => Value::SInt32($apply *v),
 
                Value::SInt64(v) => Value::SInt64($apply *v),
 
                _ => unreachable!("apply_unary_operator {:?} on value {:?}", $op, $value),
 
            };
 
        }
 
    }
 

	
 
    // If the value is a reference, retrieve the thing it is referring to
 
    let value = store.maybe_read_ref(value);
 

	
 
    match op {
 
        UO::Positive => {
 
            debug_assert!(value.is_integer());
 
            return value.clone();
 
        },
 
        UO::Negative => {
 
            // TODO: Error on negating unsigned integers
 
            return match value {
 
                Value::SInt8(v) => Value::SInt8(-*v),
 
                Value::SInt16(v) => Value::SInt16(-*v),
 
                Value::SInt32(v) => Value::SInt32(-*v),
 
                Value::SInt64(v) => Value::SInt64(-*v),
 
                _ => unreachable!("apply_unary_operator {:?} on value {:?}", op, value),
 
            }
 
        },
 
        UO::BitwiseNot => { apply_int_expr_and_return!(value, !, op)},
 
        UO::LogicalNot => { return Value::Bool(!value.as_bool()); },
 
    }
 
}
 

	
 
pub(crate) fn apply_casting(store: &mut Store, output_type: &ConcreteType, subject: &Value) -> Result<Value, String> {
 
    // To simplify the casting logic: if the output type is not a simple
 
    // integer/boolean/character, then the type checker made sure that the two
 
    // types must be equal, hence we can do a simple clone.
 
    use ConcreteTypePart as CTP;
 
    let part = &output_type.parts[0];
 
    match part {
 
        CTP::Bool | CTP::Character |
 
        CTP::UInt8 | CTP::UInt16 | CTP::UInt32 | CTP::UInt64 |
 
        CTP::SInt8 | CTP::SInt16 | CTP::SInt32 | CTP::SInt64 => {
 
            // Do the checking of these below
 
            debug_assert_eq!(output_type.parts.len(), 1);
 
        },
 
        _ => {
 
            return Ok(store.clone_value(subject.clone()));
 
        },
 
    }
 

	
 
    // Note: character is not included, needs per-type checking
 
    macro_rules! unchecked_cast {
 
        ($input: expr, $output_part: expr) => {
 
            return Ok(match $output_part {
 
                CTP::UInt8 => Value::UInt8($input as u8),
 
                CTP::UInt16 => Value::UInt16($input as u16),
 
                CTP::UInt32 => Value::UInt32($input as u32),
 
                CTP::UInt64 => Value::UInt64($input as u64),
 
                CTP::SInt8 => Value::SInt8($input as i8),
 
                CTP::SInt16 => Value::SInt16($input as i16),
 
                CTP::SInt32 => Value::SInt32($input as i32),
 
                CTP::SInt64 => Value::SInt64($input as i64),
 
                _ => unreachable!()
 
            })
 
        }
 
    }
 

	
 
    macro_rules! from_unsigned_cast {
 
        ($input:expr, $input_type:ty, $output_part:expr) => {
 
            {
 
                let target_type_name = match $output_part {
 
                    CTP::Bool => return Ok(Value::Bool($input != 0)),
 
                    CTP::Character => if $input <= u8::MAX as $input_type {
 
                        return Ok(Value::Char(($input as u8) as char))
 
                    } else {
 
                        KW_TYPE_CHAR_STR
 
                    },
 
                    CTP::UInt8 => if $input <= u8::MAX as $input_type {
 
                        return Ok(Value::UInt8($input as u8))
 
                    } else {
 
                        KW_TYPE_UINT8_STR
 
                    },
 
                    CTP::UInt16 => if $input <= u16::MAX as $input_type {
 
                        return Ok(Value::UInt16($input as u16))
 
                    } else {
 
                        KW_TYPE_UINT16_STR
 
                    },
 
                    CTP::UInt32 => if $input <= u32::MAX as $input_type {
 
                        return Ok(Value::UInt32($input as u32))
 
                    } else {
 
                        KW_TYPE_UINT32_STR
 
                    },
 
                    CTP::UInt64 => return Ok(Value::UInt64($input as u64)), // any unsigned int to u64 is fine
 
                    CTP::SInt8 => if $input <= i8::MAX as $input_type {
 
                        return Ok(Value::SInt8($input as i8))
 
                    } else {
 
                        KW_TYPE_SINT8_STR
 
                    },
 
                    CTP::SInt16 => if $input <= i16::MAX as $input_type {
 
                        return Ok(Value::SInt16($input as i16))
 
                    } else {
 
                        KW_TYPE_SINT16_STR
 
                    },
 
                    CTP::SInt32 => if $input <= i32::MAX as $input_type {
 
                        return Ok(Value::SInt32($input as i32))
 
                    } else {
 
                        KW_TYPE_SINT32_STR
 
                    },
 
                    CTP::SInt64 => if $input <= i64::MAX as $input_type {
 
                        return Ok(Value::SInt64($input as i64))
 
                    } else {
 
                        KW_TYPE_SINT64_STR
 
                    },
 
                    _ => unreachable!(),
 
                };
 

	
 
                return Err(format!("value is '{}' which doesn't fit in a type '{}'", $input, target_type_name));
 
            }
 
        }
 
    }
 

	
 
    macro_rules! from_signed_cast {
 
        // Programmer note: for signed checking we cannot do
 
        //  output_type::MAX as input_type,
 
        //
 
        // because if the output type's width is larger than the input type,
 
        // then the cast results in a negative number. So we mask with the
 
        // maximum possible value the input type can become. As in:
 
        //  (output_type::MAX as input_type) & input_type::MAX
 
        //
 
        // This way:
 
        // 1. output width is larger than input width: fine in all cases, we
 
        //  simply compare against the max input value, which is always true.
 
        // 2. output width is equal to input width: by masking we "remove the
 
        //  signed bit from the unsigned number" and again compare against the
 
        //  maximum input value.
 
        // 3. output width is smaller than the input width: masking does nothing
 
        //  because the signed bit is never set, and we simply compare against
 
        //  the maximum possible output value.
 
        //
 
        // A similar kind of mechanism for the minimum value, but here we do
 
        // a binary OR. We do a:
 
        //  (output_type::MIN as input_type) & input_type::MIN
 
        //
 
        // This way:
 
        // 1. output width is larger than input width: initial cast truncates to
 
        //  0, then we OR with the actual minimum value, so we attain the
 
        //  minimum value of the input type.
 
        // 2. output width is equal to input width: we OR the minimum value with
 
        //  itself.
 
        // 3. output width is smaller than input width: the cast produces the
 
        //  min value of the output type, the subsequent OR does nothing, as it
 
        //  essentially just sets the signed bit (which must already be set,
 
        //  since we're dealing with a signed minimum value)
 
        //
 
        // After all of this expanding, we simply hope the compiler does a best
 
        // effort constant expression evaluation, and presto!
 
        ($input:expr, $input_type:ty, $output_type:expr) => {
 
            {
 
                let target_type_name = match $output_type {
 
                    CTP::Bool => return Ok(Value::Bool($input != 0)),
 
                    CTP::Character => if $input >= 0 && $input <= (u8::max as $input_type & <$input_type>::MAX) {
 
                        return Ok(Value::Char(($input as u8) as char))
 
                    } else {
 
                        KW_TYPE_CHAR_STR
 
                    },
 
                    CTP::UInt8 => if $input >= 0 && $input <= ((u8::MAX as $input_type) & <$input_type>::MAX) {
 
                        return Ok(Value::UInt8($input as u8));
 
                    } else {
 
                        KW_TYPE_UINT8_STR
 
                    },
 
                    CTP::UInt16 => if $input >= 0 && $input <= ((u16::MAX as $input_type) & <$input_type>::MAX) {
 
                        return Ok(Value::UInt16($input as u16));
 
                    } else {
 
                        KW_TYPE_UINT16_STR
 
                    },
 
                    CTP::UInt32 => if $input >= 0 && $input <= ((u32::MAX as $input_type) & <$input_type>::MAX) {
 
                        return Ok(Value::UInt32($input as u32));
 
                    } else {
 
                        KW_TYPE_UINT32_STR
 
                    },
 
                    CTP::UInt64 => if $input >= 0 && $input <= ((u64::MAX as $input_type) & <$input_type>::MAX) {
 
                        return Ok(Value::UInt64($input as u64));
 
                    } else {
 
                        KW_TYPE_UINT64_STR
 
                    },
 
                    CTP::SInt8 => if $input >= ((i8::MIN as $input_type) | <$input_type>::MIN) && $input <= ((i8::MAX as $input_type) & <$input_type>::MAX) {
 
                        return Ok(Value::SInt8($input as i8));
 
                    } else {
 
                        KW_TYPE_SINT8_STR
 
                    },
 
                    CTP::SInt16 => if $input >= ((i16::MIN as $input_type | <$input_type>::MIN)) && $input <= ((i16::MAX as $input_type) & <$input_type>::MAX) {
 
                        return Ok(Value::SInt16($input as i16));
 
                    } else {
 
                        KW_TYPE_SINT16_STR
 
                    },
 
                    CTP::SInt32 => if $input >= ((i32::MIN as $input_type | <$input_type>::MIN)) && $input <= ((i32::MAX as $input_type) & <$input_type>::MAX) {
 
                        return Ok(Value::SInt32($input as i32));
 
                    } else {
 
                        KW_TYPE_SINT32_STR
 
                    },
 
                    CTP::SInt64 => return Ok(Value::SInt64($input as i64)),
 
                    _ => unreachable!(),
 
                };
 

	
 
                return Err(format!("value is '{}' which doesn't fit in a type '{}'", $input, target_type_name));
 
            }
 
        }
 
    }
 

	
 
    // If here, then the types might still be equal, but at least we're dealing
 
    // with a simple integer/boolean/character input and output type.
 
    let subject = store.maybe_read_ref(subject);
 
    match subject {
 
        Value::Bool(val) => {
 
            match part {
 
                CTP::Bool => return Ok(Value::Bool(*val)),
 
                CTP::Character => return Ok(Value::Char(1 as char)),
 
                _ => unchecked_cast!(*val, part),
 
            }
 
        },
 
        Value::Char(val) => {
 
            match part {
 
                CTP::Bool => return Ok(Value::Bool(*val != 0 as char)),
 
                CTP::Character => return Ok(Value::Char(*val)),
 
                _ => unchecked_cast!(*val, part),
 
            }
 
        },
 
        Value::UInt8(val) => from_unsigned_cast!(*val, u8, part),
 
        Value::UInt16(val) => from_unsigned_cast!(*val, u16, part),
 
        Value::UInt32(val) => from_unsigned_cast!(*val, u32, part),
 
        Value::UInt64(val) => from_unsigned_cast!(*val, u64, part),
 
        Value::SInt8(val) => from_signed_cast!(*val, i8, part),
 
        Value::SInt16(val) => from_signed_cast!(*val, i16, part),
 
        Value::SInt32(val) => from_signed_cast!(*val, i32, part),
 
        Value::SInt64(val) => from_signed_cast!(*val, i64, part),
 
        _ => unreachable!("mismatch between 'cast' type checking and 'cast' evaluation"),
 
    }
 
}
 

	
 
/// Recursively checks for equality.
 
pub(crate) fn apply_equality_operator(store: &Store, lhs: &Value, rhs: &Value) -> bool {
 
    let lhs = store.maybe_read_ref(lhs);
 
    let rhs = store.maybe_read_ref(rhs);
 

	
 
    fn eval_equality_heap(store: &Store, lhs_pos: HeapPos, rhs_pos: HeapPos) -> bool {
 
        let lhs_vals = &store.heap_regions[lhs_pos as usize].values;
 
        let rhs_vals = &store.heap_regions[rhs_pos as usize].values;
 
        let lhs_len = lhs_vals.len();
 
        if lhs_len != rhs_vals.len() {
 
            return false;
 
        }
 

	
 
        for idx in 0..lhs_len {
 
            let lhs_val = &lhs_vals[idx];
 
            let rhs_val = &rhs_vals[idx];
 
            if !apply_equality_operator(store, lhs_val, rhs_val) {
 
                return false;
 
            }
 
        }
 

	
 
        return true;
 
    }
 

	
 
    match lhs {
 
        Value::Input(v) => *v == rhs.as_input(),
 
        Value::Output(v) => *v == rhs.as_output(),
 
        Value::Message(lhs_pos) => eval_equality_heap(store, *lhs_pos, rhs.as_message()),
 
        Value::Null => todo!("remove null"),
 
        Value::Bool(v) => *v == rhs.as_bool(),
 
        Value::Char(v) => *v == rhs.as_char(),
 
        Value::String(lhs_pos) => eval_equality_heap(store, *lhs_pos, rhs.as_string()),
 
        Value::UInt8(v) => *v == rhs.as_uint8(),
 
        Value::UInt16(v) => *v == rhs.as_uint16(),
 
        Value::UInt32(v) => *v == rhs.as_uint32(),
 
        Value::UInt64(v) => *v == rhs.as_uint64(),
 
        Value::SInt8(v) => *v == rhs.as_sint8(),
 
        Value::SInt16(v) => *v == rhs.as_sint16(),
 
        Value::SInt32(v) => *v == rhs.as_sint32(),
 
        Value::SInt64(v) => *v == rhs.as_sint64(),
 
        Value::Array(lhs_pos) => eval_equality_heap(store, *lhs_pos, rhs.as_array()),
 
        Value::Enum(v) => *v == rhs.as_enum(),
 
        Value::Union(lhs_tag, lhs_pos) => {
 
            let (rhs_tag, rhs_pos) = rhs.as_union();
 
            if *lhs_tag != rhs_tag {
 
                return false;
 
            }
 
            eval_equality_heap(store, *lhs_pos, rhs_pos)
 
        },
 
        Value::Struct(lhs_pos) => eval_equality_heap(store, *lhs_pos, rhs.as_struct()),
 
        _ => unreachable!("apply_equality_operator to lhs {:?}", lhs),
 
    }
 
}
 

	
 
/// Recursively checks for inequality
 
pub(crate) fn apply_inequality_operator(store: &Store, lhs: &Value, rhs: &Value) -> bool {
 
    let lhs = store.maybe_read_ref(lhs);
 
    let rhs = store.maybe_read_ref(rhs);
 

	
 
    fn eval_inequality_heap(store: &Store, lhs_pos: HeapPos, rhs_pos: HeapPos) -> bool {
 
        let lhs_vals = &store.heap_regions[lhs_pos as usize].values;
 
        let rhs_vals = &store.heap_regions[rhs_pos as usize].values;
 
        let lhs_len = lhs_vals.len();
 
        if lhs_len != rhs_vals.len() {
 
            return true;
 
        }
 

	
 
        for idx in 0..lhs_len {
 
            let lhs_val = &lhs_vals[idx];
 
            let rhs_val = &rhs_vals[idx];
 
            if apply_inequality_operator(store, lhs_val, rhs_val) {
 
                return true;
 
            }
 
        }
 

	
 
        return false;
 
    }
 

	
 
    match lhs {
 
        Value::Input(v) => *v != rhs.as_input(),
 
        Value::Output(v) => *v != rhs.as_output(),
 
        Value::Message(lhs_pos) => eval_inequality_heap(store, *lhs_pos, rhs.as_message()),
 
        Value::Null => todo!("remove null"),
 
        Value::Bool(v) => *v != rhs.as_bool(),
 
        Value::Char(v) => *v != rhs.as_char(),
 
        Value::String(lhs_pos) => eval_inequality_heap(store, *lhs_pos, rhs.as_string()),
 
        Value::UInt8(v) => *v != rhs.as_uint8(),
 
        Value::UInt16(v) => *v != rhs.as_uint16(),
 
        Value::UInt32(v) => *v != rhs.as_uint32(),
 
        Value::UInt64(v) => *v != rhs.as_uint64(),
 
        Value::SInt8(v) => *v != rhs.as_sint8(),
 
        Value::SInt16(v) => *v != rhs.as_sint16(),
 
        Value::SInt32(v) => *v != rhs.as_sint32(),
 
        Value::SInt64(v) => *v != rhs.as_sint64(),
 
        Value::Array(lhs_pos) => eval_inequality_heap(store, *lhs_pos, rhs.as_array()),
 
        Value::Enum(v) => *v != rhs.as_enum(),
 
        Value::Union(lhs_tag, lhs_pos) => {
 
            let (rhs_tag, rhs_pos) = rhs.as_union();
 
            if *lhs_tag != rhs_tag {
 
                return true;
 
            }
 
            eval_inequality_heap(store, *lhs_pos, rhs_pos)
 
        },
 
        Value::Struct(lhs_pos) => eval_inequality_heap(store, *lhs_pos, rhs.as_struct()),
 
        _ => unreachable!("apply_inequality_operator to lhs {:?}", lhs)
 
    }
 
}
 

	
 
/// Recursively applies binding operator. Essentially an equality operator with
 
/// special handling if the LHS contains a binding reference to a stack
 
/// stack variable.
 
// Note: that there is a lot of `Value.clone()` going on here. As always: this
 
// is potentially cloning the references to heap values, not actually cloning
 
// those heap regions into a new heap region.
 
pub(crate) fn apply_binding_operator(store: &mut Store, lhs: Value, rhs: Value) -> bool {
 
    let lhs = store.maybe_read_ref(&lhs).clone();
 
    let rhs = store.maybe_read_ref(&rhs).clone();
 

	
 
    fn eval_binding_heap(store: &mut Store, lhs_pos: HeapPos, rhs_pos: HeapPos) -> bool {
 
        let lhs_len = store.heap_regions[lhs_pos as usize].values.len();
 
        let rhs_len = store.heap_regions[rhs_pos as usize].values.len();
 
        if lhs_len != rhs_len {
 
            return false;
 
        }
 

	
 
        for idx in 0..lhs_len {
 
            // More rust shenanigans... I'm going to calm myself by saying that
 
            // this is just a temporary evaluator implementation.
 
            let lhs_val = store.heap_regions[lhs_pos as usize].values[idx].clone();
 
            let rhs_val = store.heap_regions[rhs_pos as usize].values[idx].clone();
 
            if !apply_binding_operator(store, lhs_val, rhs_val) {
 
                return false;
 
            }
 
        }
 

	
 
        return true;
 
    }
 

	
 
    match lhs {
 
        Value::Binding(var_pos) => {
 
            let to_write = store.clone_value(rhs.clone());
 
            store.write(ValueId::Stack(var_pos), to_write);
 
            return true;
 
        },
 
        Value::Input(v) => v == rhs.as_input(),
 
        Value::Output(v) => v == rhs.as_output(),
 
        Value::Message(lhs_pos) => eval_binding_heap(store, lhs_pos, rhs.as_message()),
 
        Value::Null => todo!("remove null"),
 
        Value::Bool(v) => v == rhs.as_bool(),
 
        Value::Char(v) => v == rhs.as_char(),
 
        Value::String(lhs_pos) => eval_binding_heap(store, lhs_pos, rhs.as_string()),
 
        Value::UInt8(v) => v == rhs.as_uint8(),
 
        Value::UInt16(v) => v == rhs.as_uint16(),
 
        Value::UInt32(v) => v == rhs.as_uint32(),
 
        Value::UInt64(v) => v == rhs.as_uint64(),
 
        Value::SInt8(v) => v == rhs.as_sint8(),
 
        Value::SInt16(v) => v == rhs.as_sint16(),
 
        Value::SInt32(v) => v == rhs.as_sint32(),
 
        Value::SInt64(v) => v == rhs.as_sint64(),
 
        Value::Array(lhs_pos) => eval_binding_heap(store, lhs_pos, rhs.as_array()),
 
        Value::Enum(v) => v == rhs.as_enum(),
 
        Value::Union(lhs_tag, lhs_pos) => {
 
            let (rhs_tag, rhs_pos) = rhs.as_union();
 
            if lhs_tag != rhs_tag {
 
                return false;
 
            }
 
            eval_binding_heap(store, lhs_pos, rhs_pos)
 
        },
 
        Value::Struct(lhs_pos) => eval_binding_heap(store, lhs_pos, rhs.as_struct()),
 
        _ => unreachable!("apply_binding_operator to lhs {:?}", lhs),
 
    }
 
}
 
\ No newline at end of file
src/protocol/parser/mod.rs
Show inline comments
 
pub(crate) mod symbol_table;
 
pub(crate) mod type_table;
 
pub(crate) mod tokens;
 
pub(crate) mod token_parsing;
 
pub(crate) mod pass_tokenizer;
 
pub(crate) mod pass_symbols;
 
pub(crate) mod pass_imports;
 
pub(crate) mod pass_definitions;
 
pub(crate) mod pass_validation_linking;
 
pub(crate) mod pass_typing;
 
mod visitor;
 

	
 
use tokens::*;
 
use crate::collections::*;
 
use visitor::Visitor;
 
use pass_tokenizer::PassTokenizer;
 
use pass_symbols::PassSymbols;
 
use pass_imports::PassImport;
 
use pass_definitions::PassDefinitions;
 
use pass_validation_linking::PassValidationLinking;
 
use pass_typing::{PassTyping, ResolveQueue};
 
use symbol_table::*;
 
use type_table::TypeTable;
 

	
 
use crate::protocol::ast::*;
 
use crate::protocol::input_source::*;
 

	
 
use crate::protocol::ast_printer::ASTWriter;
 

	
 
#[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
 
pub enum ModuleCompilationPhase {
 
    Tokenized,              // source is tokenized
 
    SymbolsScanned,         // all definitions are linked to their type class
 
    ImportsResolved,        // all imports are added to the symbol table
 
    DefinitionsParsed,      // produced the AST for the entire module
 
    TypesAddedToTable,      // added all definitions to the type table
 
    ValidatedAndLinked,     // AST is traversed and has linked the required AST nodes
 
    // When we continue with the compiler:
 
    // Typed,                  // Type inference and checking has been performed
 
}
 

	
 
pub struct Module {
 
    // Buffers
 
    pub source: InputSource,
 
    pub tokens: TokenBuffer,
 
    // Identifiers
 
    pub root_id: RootId,
 
    pub name: Option<(PragmaId, StringRef<'static>)>,
 
    pub version: Option<(PragmaId, i64)>,
 
    pub phase: ModuleCompilationPhase,
 
}
 

	
 
pub struct PassCtx<'a> {
 
    heap: &'a mut Heap,
 
    symbols: &'a mut SymbolTable,
 
    pool: &'a mut StringPool,
 
}
 

	
 
pub struct Parser {
 
    // Storage of all information created/gathered during compilation.
 
    pub(crate) heap: Heap,
 
    pub(crate) string_pool: StringPool, // Do not deallocate, holds all strings
 
    pub(crate) modules: Vec<Module>,
 
    pub(crate) symbol_table: SymbolTable,
 
    pub(crate) type_table: TypeTable,
 
    // Compiler passes, used as little state machine that keep their memory
 
    // around.
 
    pass_tokenizer: PassTokenizer,
 
    pass_symbols: PassSymbols,
 
    pass_import: PassImport,
 
    pass_definitions: PassDefinitions,
 
    pass_validation: PassValidationLinking,
 
    pass_typing: PassTyping,
 
    // Compiler options
 
    pub write_ast_to: Option<String>,
 
}
 

	
 
impl Parser {
 
    pub fn new() -> Self {
 
        let mut parser = Parser{
 
            heap: Heap::new(),
 
            string_pool: StringPool::new(),
 
            modules: Vec::new(),
 
            symbol_table: SymbolTable::new(),
 
            type_table: TypeTable::new(),
 
            pass_tokenizer: PassTokenizer::new(),
 
            pass_symbols: PassSymbols::new(),
 
            pass_import: PassImport::new(),
 
            pass_definitions: PassDefinitions::new(),
 
            pass_validation: PassValidationLinking::new(),
 
            pass_typing: PassTyping::new(),
 
            write_ast_to: None,
 
        };
 

	
 
        parser.symbol_table.insert_scope(None, SymbolScope::Global);
 

	
 
        fn quick_type(variants: &[ParserTypeVariant]) -> ParserType {
 
            let mut t = ParserType{ elements: Vec::with_capacity(variants.len()) };
 
            for variant in variants {
 
                t.elements.push(ParserTypeElement{ full_span: InputSpan::new(), variant: variant.clone() });
 
            }
 
            t
 
        }
 

	
 
        use ParserTypeVariant as PTV;
 
        insert_builtin_function(&mut parser, "get", &["T"], |id| (
 
            vec![
 
                ("input", quick_type(&[PTV::Input, PTV::PolymorphicArgument(id.upcast(), 0)]))
 
            ],
 
            quick_type(&[PTV::PolymorphicArgument(id.upcast(), 0)])
 
        ));
 
        insert_builtin_function(&mut parser, "put", &["T"], |id| (
 
            vec![
 
                ("output", quick_type(&[PTV::Output, PTV::PolymorphicArgument(id.upcast(), 0)])),
 
                ("value", quick_type(&[PTV::PolymorphicArgument(id.upcast(), 0)])),
 
            ],
 
            quick_type(&[PTV::Void])
 
        ));
 
        insert_builtin_function(&mut parser, "fires", &["T"], |id| (
 
            vec![
 
                ("port", quick_type(&[PTV::InputOrOutput, PTV::PolymorphicArgument(id.upcast(), 0)]))
 
            ],
 
            quick_type(&[PTV::Bool])
 
        ));
 
        insert_builtin_function(&mut parser, "create", &["T"], |id| (
 
            vec![
 
                ("length", quick_type(&[PTV::IntegerLike]))
 
            ],
 
            quick_type(&[PTV::ArrayLike, PTV::PolymorphicArgument(id.upcast(), 0)])
 
        ));
 
        insert_builtin_function(&mut parser, "length", &["T"], |id| (
 
            vec![
 
                ("array", quick_type(&[PTV::ArrayLike, PTV::PolymorphicArgument(id.upcast(), 0)]))
 
            ],
 
            quick_type(&[PTV::UInt32]) // TODO: @PtrInt
 
        ));
 
        insert_builtin_function(&mut parser, "assert", &[], |_id| (
 
            vec![
 
                ("condition", quick_type(&[PTV::Bool])),
 
            ],
 
            quick_type(&[PTV::Void])
 
        ));
 

	
 
        parser
 
    }
 

	
 
    pub fn feed(&mut self, mut source: InputSource) -> Result<(), ParseError> {
 
        // TODO: @Optimize
 
        let mut token_buffer = TokenBuffer::new();
 
        self.pass_tokenizer.tokenize(&mut source, &mut token_buffer)?;
 

	
 
        let module = Module{
 
            source,
 
            tokens: token_buffer,
 
            root_id: RootId::new_invalid(),
 
            name: None,
 
            version: None,
 
            phase: ModuleCompilationPhase::Tokenized,
 
        };
 
        self.modules.push(module);
 

	
 
        Ok(())
 
    }
 

	
 
    pub fn parse(&mut self) -> Result<(), ParseError> {
 
        let mut pass_ctx = PassCtx{
 
            heap: &mut self.heap,
 
            symbols: &mut self.symbol_table,
 
            pool: &mut self.string_pool,
 
        };
 

	
 
        // Advance all modules to the phase where all symbols are scanned
 
        for module_idx in 0..self.modules.len() {
 
            self.pass_symbols.parse(&mut self.modules, module_idx, &mut pass_ctx)?;
 
        }
 

	
 
        // With all symbols scanned, perform further compilation until we can
 
        // add all base types to the type table.
 
        for module_idx in 0..self.modules.len() {
 
            self.pass_import.parse(&mut self.modules, module_idx, &mut pass_ctx)?;
 
            self.pass_definitions.parse(&mut self.modules, module_idx, &mut pass_ctx)?;
 
        }
 

	
 
        // Add every known type to the type table
 
        self.type_table.build_base_types(&mut self.modules, &mut pass_ctx)?;
 

	
 
        // Continue compilation with the remaining phases now that the types
 
        // are all in the type table
 
        for module_idx in 0..self.modules.len() {
 
            // TODO: Remove the entire Visitor abstraction. It really doesn't
 
            //  make sense considering the amount of special handling we do
 
            //  in each pass.
 
            let mut ctx = visitor::Ctx{
 
                heap: &mut self.heap,
 
                module: &mut self.modules[module_idx],
 
                symbols: &mut self.symbol_table,
 
                types: &mut self.type_table,
 
            };
 
            self.pass_validation.visit_module(&mut ctx)?;
 
        }
 

	
 
        // Perform typechecking on all modules
 
        let mut queue = ResolveQueue::new();
 
        for module in &mut self.modules {
 
            let mut ctx = visitor::Ctx{
 
                heap: &mut self.heap,
 
                module,
 
                symbols: &mut self.symbol_table,
 
                types: &mut self.type_table,
 
            };
 
            PassTyping::queue_module_definitions(&mut ctx, &mut queue);
 
        };
 
        while !queue.is_empty() {
 
            let top = queue.pop().unwrap();
 
            let mut ctx = visitor::Ctx{
 
                heap: &mut self.heap,
 
                module: &mut self.modules[top.root_id.index as usize],
 
                symbols: &mut self.symbol_table,
 
                types: &mut self.type_table,
 
            };
 
            self.pass_typing.handle_module_definition(&mut ctx, &mut queue, top)?;
 
        }
 

	
 
        // Write out desired information
 
        if let Some(filename) = &self.write_ast_to {
 
            let mut writer = ASTWriter::new();
 
            let mut file = std::fs::File::create(std::path::Path::new(filename)).unwrap();
 
            writer.write_ast(&mut file, &self.heap);
 
        }
 

	
 
        Ok(())
 
    }
 
}
 

	
 
// Note: args and return type need to be a function because we need to know the function ID.
 
fn insert_builtin_function<T: Fn(FunctionDefinitionId) -> (Vec<(&'static str, ParserType)>, ParserType)> (
 
    p: &mut Parser, func_name: &str, polymorphic: &[&str], arg_and_return_fn: T) {
 

	
 
    let mut poly_vars = Vec::with_capacity(polymorphic.len());
 
    for poly_var in polymorphic {
 
        poly_vars.push(Identifier{ span: InputSpan::new(), value: p.string_pool.intern(poly_var.as_bytes()) });
 
    }
 

	
 
    let func_ident_ref = p.string_pool.intern(func_name.as_bytes());
 
    let func_id = p.heap.alloc_function_definition(|this| FunctionDefinition{
 
        this,
 
        defined_in: RootId::new_invalid(),
 
        builtin: true,
 
        span: InputSpan::new(),
 
        identifier: Identifier{ span: InputSpan::new(), value: func_ident_ref.clone() },
 
        poly_vars,
 
        return_types: Vec::new(),
 
        parameters: Vec::new(),
 
        body: BlockStatementId::new_invalid(),
 
        num_expressions_in_body: -1,
 
    });
 

	
 
    let (args, ret) = arg_and_return_fn(func_id);
 

	
 
    let mut parameters = Vec::with_capacity(args.len());
 
    for (arg_name, arg_type) in args {
 
        let identifier = Identifier{ span: InputSpan::new(), value: p.string_pool.intern(arg_name.as_bytes()) };
 
        let param_id = p.heap.alloc_variable(|this| Variable{
 
            this,
 
            kind: VariableKind::Parameter,
 
            parser_type: arg_type.clone(),
 
            identifier,
 
            relative_pos_in_block: 0,
 
            unique_id_in_scope: 0
 
        });
 
        parameters.push(param_id);
 
    }
 

	
 
    let func = &mut p.heap[func_id];
 
    func.parameters = parameters;
 
    func.return_types.push(ret);
 

	
 
    p.symbol_table.insert_symbol(SymbolScope::Global, Symbol{
 
        name: func_ident_ref,
 
        variant: SymbolVariant::Definition(SymbolDefinition{
 
            defined_in_module: RootId::new_invalid(),
 
            defined_in_scope: SymbolScope::Global,
 
            definition_span: InputSpan::new(),
 
            identifier_span: InputSpan::new(),
 
            imported_at: None,
 
            class: DefinitionClass::Function,
 
            definition_id: func_id.upcast(),
 
        })
 
    }).unwrap();
 
}
 
\ No newline at end of file
src/protocol/parser/pass_definitions.rs
Show inline comments
 
@@ -151,1536 +151,1537 @@ impl PassDefinitions {
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<(), ParseError> {
 
        consume_exact_ident(&module.source, iter, KW_ENUM)?;
 
        let (ident_text, _) = consume_ident(&module.source, iter)?;
 

	
 
        // Retrieve preallocated DefinitionId
 
        let module_scope = SymbolScope::Module(module.root_id);
 
        let definition_id = ctx.symbols.get_symbol_by_name_defined_in_scope(module_scope, ident_text)
 
            .unwrap().variant.as_definition().definition_id;
 
        self.cur_definition = definition_id;
 

	
 
        // Parse enum definition
 
        consume_polymorphic_vars_spilled(&module.source, iter, ctx)?;
 

	
 
        let mut enum_section = self.enum_variants.start_section();
 
        consume_comma_separated(
 
            TokenKind::OpenCurly, TokenKind::CloseCurly, &module.source, iter, ctx,
 
            |source, iter, ctx| {
 
                let identifier = consume_ident_interned(source, iter, ctx)?;
 
                let value = if iter.next() == Some(TokenKind::Equal) {
 
                    iter.consume();
 
                    let (variant_number, _) = consume_integer_literal(source, iter, &mut self.buffer)?;
 
                    EnumVariantValue::Integer(variant_number as i64) // TODO: @int
 
                } else {
 
                    EnumVariantValue::None
 
                };
 
                Ok(EnumVariantDefinition{ identifier, value })
 
            },
 
            &mut enum_section, "an enum variant", "a list of enum variants", None
 
        )?;
 

	
 
        // Transfer to definition
 
        let enum_def = ctx.heap[definition_id].as_enum_mut();
 
        enum_def.variants = enum_section.into_vec();
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_union_definition(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<(), ParseError> {
 
        consume_exact_ident(&module.source, iter, KW_UNION)?;
 
        let (ident_text, _) = consume_ident(&module.source, iter)?;
 

	
 
        // Retrieve preallocated DefinitionId
 
        let module_scope = SymbolScope::Module(module.root_id);
 
        let definition_id = ctx.symbols.get_symbol_by_name_defined_in_scope(module_scope, ident_text)
 
            .unwrap().variant.as_definition().definition_id;
 
        self.cur_definition = definition_id;
 

	
 
        // Parse union definition
 
        consume_polymorphic_vars_spilled(&module.source, iter, ctx)?;
 

	
 
        let mut variants_section = self.union_variants.start_section();
 
        consume_comma_separated(
 
            TokenKind::OpenCurly, TokenKind::CloseCurly, &module.source, iter, ctx,
 
            |source, iter, ctx| {
 
                let identifier = consume_ident_interned(source, iter, ctx)?;
 
                let mut close_pos = identifier.span.end;
 

	
 
                let mut types_section = self.parser_types.start_section();
 

	
 
                let has_embedded = maybe_consume_comma_separated(
 
                    TokenKind::OpenParen, TokenKind::CloseParen, source, iter, ctx,
 
                    |source, iter, ctx| {
 
                        let poly_vars = ctx.heap[definition_id].poly_vars(); // TODO: @Cleanup, this is really ugly. But rust...
 
                        consume_parser_type(
 
                            source, iter, &ctx.symbols, &ctx.heap, poly_vars,
 
                            module_scope, definition_id, false, 0
 
                        )
 
                    },
 
                    &mut types_section, "an embedded type", Some(&mut close_pos)
 
                )?;
 
                let value = if has_embedded {
 
                    UnionVariantValue::Embedded(types_section.into_vec())
 
                } else {
 
                    types_section.forget();
 
                    UnionVariantValue::None
 
                };
 

	
 
                Ok(UnionVariantDefinition{
 
                    span: InputSpan::from_positions(identifier.span.begin, close_pos),
 
                    identifier,
 
                    value
 
                })
 
            },
 
            &mut variants_section, "a union variant", "a list of union variants", None
 
        )?;
 

	
 
        // Transfer to AST
 
        let union_def = ctx.heap[definition_id].as_union_mut();
 
        union_def.variants = variants_section.into_vec();
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_function_definition(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<(), ParseError> {
 
        // Retrieve function name
 
        consume_exact_ident(&module.source, iter, KW_FUNCTION)?;
 
        let (ident_text, _) = consume_ident(&module.source, iter)?;
 

	
 
        // Retrieve preallocated DefinitionId
 
        let module_scope = SymbolScope::Module(module.root_id);
 
        let definition_id = ctx.symbols.get_symbol_by_name_defined_in_scope(module_scope, ident_text)
 
            .unwrap().variant.as_definition().definition_id;
 
        self.cur_definition = definition_id;
 

	
 
        consume_polymorphic_vars_spilled(&module.source, iter, ctx)?;
 

	
 
        // Parse function's argument list
 
        let mut parameter_section = self.variables.start_section();
 
        consume_parameter_list(
 
            &module.source, iter, ctx, &mut parameter_section, module_scope, definition_id
 
        )?;
 
        let parameters = parameter_section.into_vec();
 

	
 
        // Consume return types
 
        consume_token(&module.source, iter, TokenKind::ArrowRight)?;
 
        let mut return_types = self.parser_types.start_section();
 
        let mut open_curly_pos = iter.last_valid_pos(); // bogus value
 
        consume_comma_separated_until(
 
            TokenKind::OpenCurly, &module.source, iter, ctx,
 
            |source, iter, ctx| {
 
                let poly_vars = ctx.heap[definition_id].poly_vars(); // TODO: @Cleanup, this is really ugly. But rust...
 
                consume_parser_type(source, iter, &ctx.symbols, &ctx.heap, poly_vars, module_scope, definition_id, false, 0)
 
            },
 
            &mut return_types, "a return type", Some(&mut open_curly_pos)
 
        )?;
 
        let return_types = return_types.into_vec();
 

	
 
        // TODO: @ReturnValues
 
        match return_types.len() {
 
            0 => return Err(ParseError::new_error_str_at_pos(&module.source, open_curly_pos, "expected a return type")),
 
            1 => {},
 
            _ => return Err(ParseError::new_error_str_at_pos(&module.source, open_curly_pos, "multiple return types are not (yet) allowed")),
 
        }
 

	
 
        // Consume block
 
        let body = self.consume_block_statement_without_leading_curly(module, iter, ctx, open_curly_pos)?;
 

	
 
        // Assign everything in the preallocated AST node
 
        let function = ctx.heap[definition_id].as_function_mut();
 
        function.return_types = return_types;
 
        function.parameters = parameters;
 
        function.body = body;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_component_definition(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<(), ParseError> {
 
        // Consume component variant and name
 
        let (_variant_text, _) = consume_any_ident(&module.source, iter)?;
 
        debug_assert!(_variant_text == KW_PRIMITIVE || _variant_text == KW_COMPOSITE);
 
        let (ident_text, _) = consume_ident(&module.source, iter)?;
 

	
 
        // Retrieve preallocated definition
 
        let module_scope = SymbolScope::Module(module.root_id);
 
        let definition_id = ctx.symbols.get_symbol_by_name_defined_in_scope(module_scope, ident_text)
 
            .unwrap().variant.as_definition().definition_id;
 
        self.cur_definition = definition_id;
 

	
 
        consume_polymorphic_vars_spilled(&module.source, iter, ctx)?;
 

	
 
        // Parse component's argument list
 
        let mut parameter_section = self.variables.start_section();
 
        consume_parameter_list(
 
            &module.source, iter, ctx, &mut parameter_section, module_scope, definition_id
 
        )?;
 
        let parameters = parameter_section.into_vec();
 

	
 
        // Consume block
 
        let body = self.consume_block_statement(module, iter, ctx)?;
 

	
 
        // Assign everything in the AST node
 
        let component = ctx.heap[definition_id].as_component_mut();
 
        component.parameters = parameters;
 
        component.body = body;
 

	
 
        Ok(())
 
    }
 

	
 
    /// Consumes a block statement. If the resulting statement is not a block
 
    /// (e.g. for a shorthand "if (expr) single_statement") then it will be
 
    /// wrapped in one
 
    fn consume_block_or_wrapped_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<BlockStatementId, ParseError> {
 
        if Some(TokenKind::OpenCurly) == iter.next() {
 
            // This is a block statement
 
            self.consume_block_statement(module, iter, ctx)
 
        } else {
 
            // Not a block statement, so wrap it in one
 
            let mut statements = self.statements.start_section();
 
            let wrap_begin_pos = iter.last_valid_pos();
 
            self.consume_statement(module, iter, ctx, &mut statements)?;
 
            let wrap_end_pos = iter.last_valid_pos();
 

	
 
            let statements = statements.into_vec();
 

	
 
            let id = ctx.heap.alloc_block_statement(|this| BlockStatement{
 
                this,
 
                is_implicit: true,
 
                span: InputSpan::from_positions(wrap_begin_pos, wrap_end_pos), // TODO: @Span
 
                statements,
 
                end_block: EndBlockStatementId::new_invalid(),
 
                scope_node: ScopeNode::new_invalid(),
 
                first_unique_id_in_scope: -1,
 
                next_unique_id_in_scope: -1,
 
                relative_pos_in_parent: 0,
 
                locals: Vec::new(),
 
                labels: Vec::new(),
 
                next: StatementId::new_invalid(),
 
            });
 

	
 
            let end_block = ctx.heap.alloc_end_block_statement(|this| EndBlockStatement{
 
                this, start_block: id, next: StatementId::new_invalid()
 
            });
 

	
 
            let block_stmt = &mut ctx.heap[id];
 
            block_stmt.end_block = end_block;
 

	
 
            Ok(id)
 
        }
 
    }
 

	
 
    /// Consumes a statement and returns a boolean indicating whether it was a
 
    /// block or not.
 
    fn consume_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx, section: &mut ScopedSection<StatementId>
 
    ) -> Result<(), ParseError> {
 
        let next = iter.next().expect("consume_statement has a next token");
 

	
 
        if next == TokenKind::OpenCurly {
 
            let id = self.consume_block_statement(module, iter, ctx)?;
 
            section.push(id.upcast());
 
        } else if next == TokenKind::Ident {
 
            let ident = peek_ident(&module.source, iter).unwrap();
 
            if ident == KW_STMT_IF {
 
                // Consume if statement and place end-if statement directly
 
                // after it.
 
                let id = self.consume_if_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 

	
 
                let end_if = ctx.heap.alloc_end_if_statement(|this| EndIfStatement{
 
                    this, start_if: id, next: StatementId::new_invalid()
 
                });
 
                section.push(end_if.upcast());
 

	
 
                let if_stmt = &mut ctx.heap[id];
 
                if_stmt.end_if = end_if;
 
            } else if ident == KW_STMT_WHILE {
 
                let id = self.consume_while_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 

	
 
                let end_while = ctx.heap.alloc_end_while_statement(|this| EndWhileStatement{
 
                    this, start_while: id, next: StatementId::new_invalid()
 
                });
 
                section.push(end_while.upcast());
 

	
 
                let while_stmt = &mut ctx.heap[id];
 
                while_stmt.end_while = end_while;
 
            } else if ident == KW_STMT_BREAK {
 
                let id = self.consume_break_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 
            } else if ident == KW_STMT_CONTINUE {
 
                let id = self.consume_continue_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 
            } else if ident == KW_STMT_SYNC {
 
                let id = self.consume_synchronous_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 

	
 
                let end_sync = ctx.heap.alloc_end_synchronous_statement(|this| EndSynchronousStatement{
 
                    this, start_sync: id, next: StatementId::new_invalid()
 
                });
 
                section.push(end_sync.upcast());
 

	
 
                let sync_stmt = &mut ctx.heap[id];
 
                sync_stmt.end_sync = end_sync;
 
            } else if ident == KW_STMT_RETURN {
 
                let id = self.consume_return_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 
            } else if ident == KW_STMT_GOTO {
 
                let id = self.consume_goto_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 
            } else if ident == KW_STMT_NEW {
 
                let id = self.consume_new_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 
            } else if ident == KW_STMT_CHANNEL {
 
                let id = self.consume_channel_statement(module, iter, ctx)?;
 
                section.push(id.upcast().upcast());
 
            } else if iter.peek() == Some(TokenKind::Colon) {
 
                self.consume_labeled_statement(module, iter, ctx, section)?;
 
            } else {
 
                // Two fallback possibilities: the first one is a memory
 
                // declaration, the other one is to parse it as a regular
 
                // expression. This is a bit ugly
 
                if let Some((memory_stmt_id, assignment_stmt_id)) = self.maybe_consume_memory_statement(module, iter, ctx)? {
 
                    section.push(memory_stmt_id.upcast().upcast());
 
                    section.push(assignment_stmt_id.upcast());
 
                } else {
 
                    let id = self.consume_expression_statement(module, iter, ctx)?;
 
                    section.push(id.upcast());
 
                }
 
            }
 
        } else {
 
            let id = self.consume_expression_statement(module, iter, ctx)?;
 
            section.push(id.upcast());
 
        }
 

	
 
        return Ok(());
 
    }
 

	
 
    fn consume_block_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<BlockStatementId, ParseError> {
 
        let open_span = consume_token(&module.source, iter, TokenKind::OpenCurly)?;
 
        self.consume_block_statement_without_leading_curly(module, iter, ctx, open_span.begin)
 
    }
 

	
 
    fn consume_block_statement_without_leading_curly(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx, open_curly_pos: InputPosition
 
    ) -> Result<BlockStatementId, ParseError> {
 
        let mut stmt_section = self.statements.start_section();
 
        let mut next = iter.next();
 
        while next != Some(TokenKind::CloseCurly) {
 
            if next.is_none() {
 
                return Err(ParseError::new_error_str_at_pos(
 
                    &module.source, iter.last_valid_pos(), "expected a statement or '}'"
 
                ));
 
            }
 
            self.consume_statement(module, iter, ctx, &mut stmt_section)?;
 
            next = iter.next();
 
        }
 

	
 
        let statements = stmt_section.into_vec();
 
        let mut block_span = consume_token(&module.source, iter, TokenKind::CloseCurly)?;
 
        block_span.begin = open_curly_pos;
 

	
 
        let id = ctx.heap.alloc_block_statement(|this| BlockStatement{
 
            this,
 
            is_implicit: false,
 
            span: block_span,
 
            statements,
 
            end_block: EndBlockStatementId::new_invalid(),
 
            scope_node: ScopeNode::new_invalid(),
 
            first_unique_id_in_scope: -1,
 
            next_unique_id_in_scope: -1,
 
            relative_pos_in_parent: 0,
 
            locals: Vec::new(),
 
            labels: Vec::new(),
 
            next: StatementId::new_invalid(),
 
        });
 

	
 
        let end_block = ctx.heap.alloc_end_block_statement(|this| EndBlockStatement{
 
            this, start_block: id, next: StatementId::new_invalid()
 
        });
 

	
 
        let block_stmt = &mut ctx.heap[id];
 
        block_stmt.end_block = end_block;
 

	
 
        Ok(id)
 
    }
 

	
 
    fn consume_if_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<IfStatementId, ParseError> {
 
        let if_span = consume_exact_ident(&module.source, iter, KW_STMT_IF)?;
 
        consume_token(&module.source, iter, TokenKind::OpenParen)?;
 
        let test = self.consume_expression(module, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::CloseParen)?;
 
        let true_body = self.consume_block_or_wrapped_statement(module, iter, ctx)?;
 

	
 
        let false_body = if has_ident(&module.source, iter, KW_STMT_ELSE) {
 
            iter.consume();
 
            let false_body = self.consume_block_or_wrapped_statement(module, iter, ctx)?;
 
            Some(false_body)
 
        } else {
 
            None
 
        };
 

	
 
        Ok(ctx.heap.alloc_if_statement(|this| IfStatement{
 
            this,
 
            span: if_span,
 
            test,
 
            true_body,
 
            false_body,
 
            end_if: EndIfStatementId::new_invalid(),
 
        }))
 
    }
 

	
 
    fn consume_while_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<WhileStatementId, ParseError> {
 
        let while_span = consume_exact_ident(&module.source, iter, KW_STMT_WHILE)?;
 
        consume_token(&module.source, iter, TokenKind::OpenParen)?;
 
        let test = self.consume_expression(module, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::CloseParen)?;
 
        let body = self.consume_block_or_wrapped_statement(module, iter, ctx)?;
 

	
 
        Ok(ctx.heap.alloc_while_statement(|this| WhileStatement{
 
            this,
 
            span: while_span,
 
            test,
 
            body,
 
            end_while: EndWhileStatementId::new_invalid(),
 
            in_sync: SynchronousStatementId::new_invalid(),
 
        }))
 
    }
 

	
 
    fn consume_break_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<BreakStatementId, ParseError> {
 
        let break_span = consume_exact_ident(&module.source, iter, KW_STMT_BREAK)?;
 
        let label = if Some(TokenKind::Ident) == iter.next() {
 
            let label = consume_ident_interned(&module.source, iter, ctx)?;
 
            Some(label)
 
        } else {
 
            None
 
        };
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 
        Ok(ctx.heap.alloc_break_statement(|this| BreakStatement{
 
            this,
 
            span: break_span,
 
            label,
 
            target: None,
 
        }))
 
    }
 

	
 
    fn consume_continue_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ContinueStatementId, ParseError> {
 
        let continue_span = consume_exact_ident(&module.source, iter, KW_STMT_CONTINUE)?;
 
        let label=  if Some(TokenKind::Ident) == iter.next() {
 
            let label = consume_ident_interned(&module.source, iter, ctx)?;
 
            Some(label)
 
        } else {
 
            None
 
        };
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 
        Ok(ctx.heap.alloc_continue_statement(|this| ContinueStatement{
 
            this,
 
            span: continue_span,
 
            label,
 
            target: None
 
        }))
 
    }
 

	
 
    fn consume_synchronous_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<SynchronousStatementId, ParseError> {
 
        let synchronous_span = consume_exact_ident(&module.source, iter, KW_STMT_SYNC)?;
 
        let body = self.consume_block_or_wrapped_statement(module, iter, ctx)?;
 

	
 
        Ok(ctx.heap.alloc_synchronous_statement(|this| SynchronousStatement{
 
            this,
 
            span: synchronous_span,
 
            body,
 
            end_sync: EndSynchronousStatementId::new_invalid(),
 
        }))
 
    }
 

	
 
    fn consume_return_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ReturnStatementId, ParseError> {
 
        let return_span = consume_exact_ident(&module.source, iter, KW_STMT_RETURN)?;
 
        let mut scoped_section = self.expressions.start_section();
 

	
 
        consume_comma_separated_until(
 
            TokenKind::SemiColon, &module.source, iter, ctx,
 
            |_source, iter, ctx| self.consume_expression(module, iter, ctx),
 
            &mut scoped_section, "a return expression", None
 
        )?;
 
        let expressions = scoped_section.into_vec();
 

	
 
        if expressions.is_empty() {
 
            return Err(ParseError::new_error_str_at_span(&module.source, return_span, "expected at least one return value"));
 
        } else if expressions.len() > 1 {
 
            return Err(ParseError::new_error_str_at_span(&module.source, return_span, "multiple return values are not (yet) supported"))
 
        }
 

	
 
        Ok(ctx.heap.alloc_return_statement(|this| ReturnStatement{
 
            this,
 
            span: return_span,
 
            expressions
 
        }))
 
    }
 

	
 
    fn consume_goto_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<GotoStatementId, ParseError> {
 
        let goto_span = consume_exact_ident(&module.source, iter, KW_STMT_GOTO)?;
 
        let label = consume_ident_interned(&module.source, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 
        Ok(ctx.heap.alloc_goto_statement(|this| GotoStatement{
 
            this,
 
            span: goto_span,
 
            label,
 
            target: None
 
        }))
 
    }
 

	
 
    fn consume_new_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<NewStatementId, ParseError> {
 
        let new_span = consume_exact_ident(&module.source, iter, KW_STMT_NEW)?;
 

	
 
        // TODO: @Cleanup, should just call something like consume_component_expression-ish
 
        let start_pos = iter.last_valid_pos();
 
        let expression_id = self.consume_primary_expression(module, iter, ctx)?;
 
        let expression = &ctx.heap[expression_id];
 
        let mut valid = false;
 

	
 
        let mut call_id = CallExpressionId::new_invalid();
 
        if let Expression::Call(expression) = expression {
 
            // Allow both components and functions, as it makes more sense to
 
            // check their correct use in the validation and linking pass
 
            if expression.method == Method::UserComponent || expression.method == Method::UserFunction {
 
                call_id = expression.this;
 
                valid = true;
 
            }
 
        }
 

	
 
        if !valid {
 
            return Err(ParseError::new_error_str_at_span(
 
                &module.source, InputSpan::from_positions(start_pos, iter.last_valid_pos()), "expected a call expression"
 
            ));
 
        }
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 

	
 
        debug_assert!(!call_id.is_invalid());
 
        Ok(ctx.heap.alloc_new_statement(|this| NewStatement{
 
            this,
 
            span: new_span,
 
            expression: call_id,
 
            next: StatementId::new_invalid(),
 
        }))
 
    }
 

	
 
    fn consume_channel_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ChannelStatementId, ParseError> {
 
        // Consume channel specification
 
        let channel_span = consume_exact_ident(&module.source, iter, KW_STMT_CHANNEL)?;
 
        let inner_port_type = if Some(TokenKind::OpenAngle) == iter.next() {
 
            // Retrieve the type of the channel, we're cheating a bit here by
 
            // consuming the first '<' and setting the initial angle depth to 1
 
            // such that our final '>' will be consumed as well.
 
            iter.consume();
 
            let definition_id = self.cur_definition;
 
            let poly_vars = ctx.heap[definition_id].poly_vars();
 
            consume_parser_type(
 
                &module.source, iter, &ctx.symbols, &ctx.heap,
 
                poly_vars, SymbolScope::Module(module.root_id), definition_id,
 
                true, 1
 
            )?
 
        } else {
 
            // Assume inferred
 
            ParserType{ elements: vec![ParserTypeElement{
 
                full_span: channel_span, // TODO: @Span fix
 
                variant: ParserTypeVariant::Inferred
 
            }]}
 
        };
 

	
 
        let from_identifier = consume_ident_interned(&module.source, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::ArrowRight)?;
 
        let to_identifier = consume_ident_interned(&module.source, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 

	
 
        // Construct ports
 
        let port_type_len = inner_port_type.elements.len() + 1;
 
        let mut from_port_type = ParserType{ elements: Vec::with_capacity(port_type_len) };
 
        from_port_type.elements.push(ParserTypeElement{ full_span: channel_span, variant: ParserTypeVariant::Output });
 
        from_port_type.elements.extend_from_slice(&inner_port_type.elements);
 
        let from = ctx.heap.alloc_variable(|this| Variable{
 
            this,
 
            kind: VariableKind::Local,
 
            identifier: from_identifier,
 
            parser_type: from_port_type,
 
            relative_pos_in_block: 0,
 
            unique_id_in_scope: -1,
 
        });
 

	
 
        let mut to_port_type = ParserType{ elements: Vec::with_capacity(port_type_len) };
 
        to_port_type.elements.push(ParserTypeElement{ full_span: channel_span, variant: ParserTypeVariant::Input });
 
        to_port_type.elements.extend_from_slice(&inner_port_type.elements);
 
        let to = ctx.heap.alloc_variable(|this|Variable{
 
            this,
 
            kind: VariableKind::Local,
 
            identifier: to_identifier,
 
            parser_type: to_port_type,
 
            relative_pos_in_block: 0,
 
            unique_id_in_scope: -1,
 
        });
 

	
 
        // Construct the channel
 
        Ok(ctx.heap.alloc_channel_statement(|this| ChannelStatement{
 
            this,
 
            span: channel_span,
 
            from, to,
 
            relative_pos_in_block: 0,
 
            next: StatementId::new_invalid(),
 
        }))
 
    }
 

	
 
    fn consume_labeled_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx, section: &mut ScopedSection<StatementId>
 
    ) -> Result<(), ParseError> {
 
        let label = consume_ident_interned(&module.source, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::Colon)?;
 

	
 
        // Not pretty: consume_statement may produce more than one statement.
 
        // The values in the section need to be in the correct order if some
 
        // kind of outer block is consumed, so we take another section, push
 
        // the expressions in that one, and then allocate the labeled statement.
 
        let mut inner_section = self.statements.start_section();
 
        self.consume_statement(module, iter, ctx, &mut inner_section)?;
 
        debug_assert!(inner_section.len() >= 1);
 

	
 
        let stmt_id = ctx.heap.alloc_labeled_statement(|this| LabeledStatement {
 
            this,
 
            label,
 
            body: inner_section[0],
 
            relative_pos_in_block: 0,
 
            in_sync: SynchronousStatementId::new_invalid(),
 
        });
 

	
 
        if inner_section.len() == 1 {
 
            // Produce the labeled statement pointing to the first statement.
 
            // This is by far the most common case.
 
            inner_section.forget();
 
            section.push(stmt_id.upcast());
 
        } else {
 
            // Produce the labeled statement using the first statement, and push
 
            // the remaining ones at the end.
 
            let inner_statements = inner_section.into_vec();
 
            section.push(stmt_id.upcast());
 
            for idx in 1..inner_statements.len() {
 
                section.push(inner_statements[idx])
 
            }
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn maybe_consume_memory_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<Option<(MemoryStatementId, ExpressionStatementId)>, ParseError> {
 
        // This is a bit ugly. It would be nicer if we could somehow
 
        // consume the expression with a type hint if we do get a valid
 
        // type, but we don't get an identifier following it
 
        let iter_state = iter.save();
 
        let definition_id = self.cur_definition;
 
        let poly_vars = ctx.heap[definition_id].poly_vars();
 

	
 
        let parser_type = consume_parser_type(
 
            &module.source, iter, &ctx.symbols, &ctx.heap, poly_vars,
 
            SymbolScope::Definition(definition_id), definition_id, true, 0
 
        );
 

	
 
        if let Ok(parser_type) = parser_type {
 
            if Some(TokenKind::Ident) == iter.next() {
 
                // Assume this is a proper memory statement
 
                let identifier = consume_ident_interned(&module.source, iter, ctx)?;
 
                let memory_span = InputSpan::from_positions(parser_type.elements[0].full_span.begin, identifier.span.end);
 
                let assign_span = consume_token(&module.source, iter, TokenKind::Equal)?;
 

	
 
                let initial_expr_begin_pos = iter.last_valid_pos();
 
                let initial_expr_id = self.consume_expression(module, iter, ctx)?;
 
                let initial_expr_end_pos = iter.last_valid_pos();
 
                consume_token(&module.source, iter, TokenKind::SemiColon)?;
 

	
 
                // Allocate the memory statement with the variable
 
                let local_id = ctx.heap.alloc_variable(|this| Variable{
 
                    this,
 
                    kind: VariableKind::Local,
 
                    identifier: identifier.clone(),
 
                    parser_type,
 
                    relative_pos_in_block: 0,
 
                    unique_id_in_scope: -1,
 
                });
 
                let memory_stmt_id = ctx.heap.alloc_memory_statement(|this| MemoryStatement{
 
                    this,
 
                    span: memory_span,
 
                    variable: local_id,
 
                    next: StatementId::new_invalid()
 
                });
 

	
 
                // Allocate the initial assignment
 
                let variable_expr_id = ctx.heap.alloc_variable_expression(|this| VariableExpression{
 
                    this,
 
                    identifier,
 
                    declaration: None,
 
                    used_as_binding_target: false,
 
                    parent: ExpressionParent::None,
 
                    unique_id_in_definition: -1,
 
                });
 
                let assignment_expr_id = ctx.heap.alloc_assignment_expression(|this| AssignmentExpression{
 
                    this,
 
                    span: assign_span,
 
                    left: variable_expr_id.upcast(),
 
                    operation: AssignmentOperator::Set,
 
                    right: initial_expr_id,
 
                    parent: ExpressionParent::None,
 
                    unique_id_in_definition: -1,
 
                });
 
                let assignment_stmt_id = ctx.heap.alloc_expression_statement(|this| ExpressionStatement{
 
                    this,
 
                    span: InputSpan::from_positions(initial_expr_begin_pos, initial_expr_end_pos),
 
                    expression: assignment_expr_id.upcast(),
 
                    next: StatementId::new_invalid(),
 
                });
 

	
 
                return Ok(Some((memory_stmt_id, assignment_stmt_id)))
 
            }
 
        }
 

	
 
        // If here then one of the preconditions for a memory statement was not
 
        // met. So recover the iterator and return
 
        iter.load(iter_state);
 
        Ok(None)
 
    }
 

	
 
    fn consume_expression_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionStatementId, ParseError> {
 
        let start_pos = iter.last_valid_pos();
 
        let expression = self.consume_expression(module, iter, ctx)?;
 
        let end_pos = iter.last_valid_pos();
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 

	
 
        Ok(ctx.heap.alloc_expression_statement(|this| ExpressionStatement{
 
            this,
 
            span: InputSpan::from_positions(start_pos, end_pos),
 
            expression,
 
            next: StatementId::new_invalid(),
 
        }))
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // Expression Parsing
 
    //--------------------------------------------------------------------------
 

	
 
    // TODO: @Cleanup This is fine for now. But I prefer my stacktraces not to
 
    //  look like enterprise Java code...
 
    fn consume_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_assignment_expression(module, iter, ctx)
 
    }
 

	
 
    fn consume_assignment_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        // Utility to convert token into assignment operator
 
        fn parse_assignment_operator(token: Option<TokenKind>) -> Option<AssignmentOperator> {
 
            use TokenKind as TK;
 
            use AssignmentOperator as AO;
 

	
 
            if token.is_none() {
 
                return None
 
            }
 

	
 
            match token.unwrap() {
 
                TK::Equal               => Some(AO::Set),
 
                TK::AtEquals            => Some(AO::Concatenated),
 
                TK::StarEquals          => Some(AO::Multiplied),
 
                TK::SlashEquals         => Some(AO::Divided),
 
                TK::PercentEquals       => Some(AO::Remained),
 
                TK::PlusEquals          => Some(AO::Added),
 
                TK::MinusEquals         => Some(AO::Subtracted),
 
                TK::ShiftLeftEquals     => Some(AO::ShiftedLeft),
 
                TK::ShiftRightEquals    => Some(AO::ShiftedRight),
 
                TK::AndEquals           => Some(AO::BitwiseAnded),
 
                TK::CaretEquals         => Some(AO::BitwiseXored),
 
                TK::OrEquals            => Some(AO::BitwiseOred),
 
                _                       => None
 
            }
 
        }
 

	
 
        let expr = self.consume_conditional_expression(module, iter, ctx)?;
 
        if let Some(operation) = parse_assignment_operator(iter.next()) {
 
            let span = iter.next_span();
 
            iter.consume();
 

	
 
            let left = expr;
 
            let right = self.consume_expression(module, iter, ctx)?;
 

	
 
            Ok(ctx.heap.alloc_assignment_expression(|this| AssignmentExpression{
 
                this, span, left, operation, right,
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast())
 
        } else {
 
            Ok(expr)
 
        }
 
    }
 

	
 
    fn consume_conditional_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        let result = self.consume_concat_expression(module, iter, ctx)?;
 
        if let Some(TokenKind::Question) = iter.next() {
 
            let span = iter.next_span();
 
            iter.consume();
 

	
 
            let test = result;
 
            let true_expression = self.consume_expression(module, iter, ctx)?;
 
            consume_token(&module.source, iter, TokenKind::Colon)?;
 
            let false_expression = self.consume_expression(module, iter, ctx)?;
 
            Ok(ctx.heap.alloc_conditional_expression(|this| ConditionalExpression{
 
                this, span, test, true_expression, false_expression,
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast())
 
        } else {
 
            Ok(result)
 
        }
 
    }
 

	
 
    fn consume_concat_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::At) => Some(BinaryOperator::Concatenate),
 
                _ => None
 
            },
 
            Self::consume_logical_or_expression
 
        )
 
    }
 

	
 
    fn consume_logical_or_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::OrOr) => Some(BinaryOperator::LogicalOr),
 
                _ => None
 
            },
 
            Self::consume_logical_and_expression
 
        )
 
    }
 

	
 
    fn consume_logical_and_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::AndAnd) => Some(BinaryOperator::LogicalAnd),
 
                _ => None
 
            },
 
            Self::consume_bitwise_or_expression
 
        )
 
    }
 

	
 
    fn consume_bitwise_or_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::Or) => Some(BinaryOperator::BitwiseOr),
 
                _ => None
 
            },
 
            Self::consume_bitwise_xor_expression
 
        )
 
    }
 

	
 
    fn consume_bitwise_xor_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::Caret) => Some(BinaryOperator::BitwiseXor),
 
                _ => None
 
            },
 
            Self::consume_bitwise_and_expression
 
        )
 
    }
 

	
 
    fn consume_bitwise_and_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::And) => Some(BinaryOperator::BitwiseAnd),
 
                _ => None
 
            },
 
            Self::consume_equality_expression
 
        )
 
    }
 

	
 
    fn consume_equality_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::EqualEqual) => Some(BinaryOperator::Equality),
 
                Some(TokenKind::NotEqual) => Some(BinaryOperator::Inequality),
 
                _ => None
 
            },
 
            Self::consume_relational_expression
 
        )
 
    }
 

	
 
    fn consume_relational_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::OpenAngle) => Some(BinaryOperator::LessThan),
 
                Some(TokenKind::CloseAngle) => Some(BinaryOperator::GreaterThan),
 
                Some(TokenKind::LessEquals) => Some(BinaryOperator::LessThanEqual),
 
                Some(TokenKind::GreaterEquals) => Some(BinaryOperator::GreaterThanEqual),
 
                _ => None
 
            },
 
            Self::consume_shift_expression
 
        )
 
    }
 

	
 
    fn consume_shift_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::ShiftLeft) => Some(BinaryOperator::ShiftLeft),
 
                Some(TokenKind::ShiftRight) => Some(BinaryOperator::ShiftRight),
 
                _ => None
 
            },
 
            Self::consume_add_or_subtract_expression
 
        )
 
    }
 

	
 
    fn consume_add_or_subtract_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::Plus) => Some(BinaryOperator::Add),
 
                Some(TokenKind::Minus) => Some(BinaryOperator::Subtract),
 
                _ => None,
 
            },
 
            Self::consume_multiply_divide_or_modulus_expression
 
        )
 
    }
 

	
 
    fn consume_multiply_divide_or_modulus_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::Star) => Some(BinaryOperator::Multiply),
 
                Some(TokenKind::Slash) => Some(BinaryOperator::Divide),
 
                Some(TokenKind::Percent) => Some(BinaryOperator::Remainder),
 
                _ => None
 
            },
 
            Self::consume_prefix_expression
 
        )
 
    }
 

	
 
    fn consume_prefix_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        fn parse_prefix_token(token: Option<TokenKind>) -> Option<UnaryOperator> {
 
            use TokenKind as TK;
 
            use UnaryOperator as UO;
 
            match token {
 
                Some(TK::Plus) => Some(UO::Positive),
 
                Some(TK::Minus) => Some(UO::Negative),
 
                Some(TK::Tilde) => Some(UO::BitwiseNot),
 
                Some(TK::Exclamation) => Some(UO::LogicalNot),
 
                _ => None
 
            }
 
        }
 

	
 
        let next = iter.next();
 
        if let Some(operation) = parse_prefix_token(next) {
 
            let span = iter.next_span();
 
            iter.consume();
 

	
 
            let expression = self.consume_prefix_expression(module, iter, ctx)?;
 
            Ok(ctx.heap.alloc_unary_expression(|this| UnaryExpression {
 
                this,
 
                span,
 
                operation,
 
                expression,
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast())
 
        } else if next == Some(TokenKind::PlusPlus) {
 
            return Err(ParseError::new_error_str_at_span(
 
                &module.source, iter.next_span(), "prefix increment is not supported in the language"
 
            ));
 
        } else if next == Some(TokenKind::MinusMinus) {
 
            return Err(ParseError::new_error_str_at_span(
 
                &module.source, iter.next_span(), "prefix decrement is not supported in this language"
 
            ));
 
        } else {
 
            self.consume_postfix_expression(module, iter, ctx)
 
        }
 
    }
 

	
 
    fn consume_postfix_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        fn has_matching_postfix_token(token: Option<TokenKind>) -> bool {
 
            use TokenKind as TK;
 

	
 
            if token.is_none() { return false; }
 
            match token.unwrap() {
 
                TK::PlusPlus | TK::MinusMinus | TK::OpenSquare | TK::Dot => true,
 
                _ => false
 
            }
 
        }
 

	
 
        let mut result = self.consume_primary_expression(module, iter, ctx)?;
 
        let mut next = iter.next();
 
        while has_matching_postfix_token(next) {
 
            let token = next.unwrap();
 
            let mut span = iter.next_span();
 
            iter.consume();
 

	
 
            if token == TokenKind::PlusPlus {
 
                return Err(ParseError::new_error_str_at_span(
 
                    &module.source, span, "postfix increment is not supported in this language"
 
                ));
 
            } else if token == TokenKind::MinusMinus {
 
                return Err(ParseError::new_error_str_at_span(
 
                    &module.source, span, "prefix increment is not supported in this language"
 
                ));
 
            } else if token == TokenKind::OpenSquare {
 
                let subject = result;
 
                let from_index = self.consume_expression(module, iter, ctx)?;
 

	
 
                // Check if we have an indexing or slicing operation
 
                next = iter.next();
 
                if Some(TokenKind::DotDot) == next {
 
                    iter.consume();
 

	
 
                    let to_index = self.consume_expression(module, iter, ctx)?;
 
                    let end_span = consume_token(&module.source, iter, TokenKind::CloseSquare)?;
 
                    span.end = end_span.end;
 

	
 
                    result = ctx.heap.alloc_slicing_expression(|this| SlicingExpression{
 
                        this, span, subject, from_index, to_index,
 
                        parent: ExpressionParent::None,
 
                        unique_id_in_definition: -1,
 
                    }).upcast();
 
                } else if Some(TokenKind::CloseSquare) == next {
 
                    let end_span = consume_token(&module.source, iter, TokenKind::CloseSquare)?;
 
                    span.end = end_span.end;
 

	
 
                    result = ctx.heap.alloc_indexing_expression(|this| IndexingExpression{
 
                        this, span, subject,
 
                        index: from_index,
 
                        parent: ExpressionParent::None,
 
                        unique_id_in_definition: -1,
 
                    }).upcast();
 
                } else {
 
                    return Err(ParseError::new_error_str_at_pos(
 
                        &module.source, iter.last_valid_pos(), "unexpected token: expected ']' or '..'"
 
                    ));
 
                }
 
            } else {
 
                debug_assert_eq!(token, TokenKind::Dot);
 
                let subject = result;
 
                let field_name = consume_ident_interned(&module.source, iter, ctx)?;
 

	
 
                result = ctx.heap.alloc_select_expression(|this| SelectExpression{
 
                    this, span, subject, field_name,
 
                    parent: ExpressionParent::None,
 
                    unique_id_in_definition: -1,
 
                }).upcast();
 
            }
 

	
 
            next = iter.next();
 
        }
 

	
 
        Ok(result)
 
    }
 

	
 
    fn consume_primary_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        let next = iter.next();
 

	
 
        let result = if next == Some(TokenKind::OpenParen) {
 
            // Expression between parentheses
 
            iter.consume();
 
            let result = self.consume_expression(module, iter, ctx)?;
 
            consume_token(&module.source, iter, TokenKind::CloseParen)?;
 

	
 
            result
 
        } else if next == Some(TokenKind::OpenCurly) {
 
            // Array literal
 
            let (start_pos, mut end_pos) = iter.next_positions();
 
            let mut scoped_section = self.expressions.start_section();
 
            consume_comma_separated(
 
                TokenKind::OpenCurly, TokenKind::CloseCurly, &module.source, iter, ctx,
 
                |_source, iter, ctx| self.consume_expression(module, iter, ctx),
 
                &mut scoped_section, "an expression", "a list of expressions", Some(&mut end_pos)
 
            )?;
 

	
 
            ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                this,
 
                span: InputSpan::from_positions(start_pos, end_pos),
 
                value: Literal::Array(scoped_section.into_vec()),
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast()
 
        } else if next == Some(TokenKind::Integer) {
 
            let (literal, span) = consume_integer_literal(&module.source, iter, &mut self.buffer)?;
 

	
 
            ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                this, span,
 
                value: Literal::Integer(LiteralInteger{ unsigned_value: literal, negated: false }),
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast()
 
        } else if next == Some(TokenKind::String) {
 
            let span = consume_string_literal(&module.source, iter, &mut self.buffer)?;
 
            let interned = ctx.pool.intern(self.buffer.as_bytes());
 

	
 
            ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                this, span,
 
                value: Literal::String(interned),
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast()
 
        } else if next == Some(TokenKind::Character) {
 
            let (character, span) = consume_character_literal(&module.source, iter)?;
 

	
 
            ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                this, span,
 
                value: Literal::Character(character),
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast()
 
        } else if next == Some(TokenKind::Ident) {
 
            // May be a variable, a type instantiation or a function call. If we
 
            // have a single identifier that we cannot find in the type table
 
            // then we're going to assume that we're dealing with a variable.
 
            let ident_span = iter.next_span();
 
            let ident_text = module.source.section_at_span(ident_span);
 
            let symbol = ctx.symbols.get_symbol_by_name(SymbolScope::Module(module.root_id), ident_text);
 

	
 
            if symbol.is_some() {
 
                // The first bit looked like a symbol, so we're going to follow
 
                // that all the way through, assume we arrive at some kind of
 
                // function call or type instantiation
 
                use ParserTypeVariant as PTV;
 

	
 
                let symbol_scope = SymbolScope::Definition(self.cur_definition);
 
                let poly_vars = ctx.heap[self.cur_definition].poly_vars();
 
                let parser_type = consume_parser_type(
 
                    &module.source, iter, &ctx.symbols, &ctx.heap, poly_vars, symbol_scope,
 
                    self.cur_definition, true, 0
 
                )?;
 
                debug_assert!(!parser_type.elements.is_empty());
 
                match parser_type.elements[0].variant {
 
                    PTV::Definition(target_definition_id, _) => {
 
                        let definition = &ctx.heap[target_definition_id];
 
                        match definition {
 
                            Definition::Struct(_) => {
 
                                // Struct literal
 
                                let mut last_token = iter.last_valid_pos();
 
                                let mut struct_fields = Vec::new();
 
                                consume_comma_separated(
 
                                    TokenKind::OpenCurly, TokenKind::CloseCurly, &module.source, iter, ctx,
 
                                    |source, iter, ctx| {
 
                                        let identifier = consume_ident_interned(source, iter, ctx)?;
 
                                        consume_token(source, iter, TokenKind::Colon)?;
 
                                        let value = self.consume_expression(module, iter, ctx)?;
 
                                        Ok(LiteralStructField{ identifier, value, field_idx: 0 })
 
                                    },
 
                                    &mut struct_fields, "a struct field", "a list of struct fields", Some(&mut last_token)
 
                                )?;
 

	
 
                                ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                                    this,
 
                                    span: InputSpan::from_positions(ident_span.begin, last_token),
 
                                    value: Literal::Struct(LiteralStruct{
 
                                        parser_type,
 
                                        fields: struct_fields,
 
                                        definition: target_definition_id,
 
                                    }),
 
                                    parent: ExpressionParent::None,
 
                                    unique_id_in_definition: -1,
 
                                }).upcast()
 
                            },
 
                            Definition::Enum(_) => {
 
                                // Enum literal: consume the variant
 
                                consume_token(&module.source, iter, TokenKind::ColonColon)?;
 
                                let variant = consume_ident_interned(&module.source, iter, ctx)?;
 

	
 
                                ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                                    this,
 
                                    span: InputSpan::from_positions(ident_span.begin, variant.span.end),
 
                                    value: Literal::Enum(LiteralEnum{
 
                                        parser_type,
 
                                        variant,
 
                                        definition: target_definition_id,
 
                                        variant_idx: 0
 
                                    }),
 
                                    parent: ExpressionParent::None,
 
                                    unique_id_in_definition: -1,
 
                                }).upcast()
 
                            },
 
                            Definition::Union(_) => {
 
                                // Union literal: consume the variant
 
                                consume_token(&module.source, iter, TokenKind::ColonColon)?;
 
                                let variant = consume_ident_interned(&module.source, iter, ctx)?;
 

	
 
                                // Consume any possible embedded values
 
                                let mut end_pos = variant.span.end;
 
                                let values = if Some(TokenKind::OpenParen) == iter.next() {
 
                                    self.consume_expression_list(module, iter, ctx, Some(&mut end_pos))?
 
                                } else {
 
                                    Vec::new()
 
                                };
 

	
 
                                ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                                    this,
 
                                    span: InputSpan::from_positions(ident_span.begin, end_pos),
 
                                    value: Literal::Union(LiteralUnion{
 
                                        parser_type, variant, values,
 
                                        definition: target_definition_id,
 
                                        variant_idx: 0,
 
                                    }),
 
                                    parent: ExpressionParent::None,
 
                                    unique_id_in_definition: -1,
 
                                }).upcast()
 
                            },
 
                            Definition::Component(_) => {
 
                                // Component instantiation
 
                                let arguments = self.consume_expression_list(module, iter, ctx, None)?;
 

	
 
                                ctx.heap.alloc_call_expression(|this| CallExpression{
 
                                    this,
 
                                    span: parser_type.elements[0].full_span, // TODO: @Span fix
 
                                    parser_type,
 
                                    method: Method::UserComponent,
 
                                    arguments,
 
                                    definition: target_definition_id,
 
                                    parent: ExpressionParent::None,
 
                                    unique_id_in_definition: -1,
 
                                }).upcast()
 
                            },
 
                            Definition::Function(function_definition) => {
 
                                // Check whether it is a builtin function
 
                                let method = if function_definition.builtin {
 
                                    match function_definition.identifier.value.as_str() {
 
                                        "get" => Method::Get,
 
                                        "put" => Method::Put,
 
                                        "fires" => Method::Fires,
 
                                        "create" => Method::Create,
 
                                        "length" => Method::Length,
 
                                        "assert" => Method::Assert,
 
                                        _ => unreachable!(),
 
                                    }
 
                                } else {
 
                                    Method::UserFunction
 
                                };
 

	
 
                                // Function call: consume the arguments
 
                                let arguments = self.consume_expression_list(module, iter, ctx, None)?;
 

	
 
                                ctx.heap.alloc_call_expression(|this| CallExpression{
 
                                    this,
 
                                    span: parser_type.elements[0].full_span, // TODO: @Span fix
 
                                    parser_type,
 
                                    method,
 
                                    arguments,
 
                                    definition: target_definition_id,
 
                                    parent: ExpressionParent::None,
 
                                    unique_id_in_definition: -1,
 
                                }).upcast()
 
                            }
 
                        }
 
                    },
 
                    _ => {
 
                        return Err(ParseError::new_error_str_at_span(
 
                            &module.source, parser_type.elements[0].full_span,
 
                            "unexpected type in expression, note that casting expressions are not yet implemented"
 
                        ))
 
                    }
 
                }
 
            } else {
 
                // Check for builtin keywords or builtin functions
 
                if ident_text == KW_LIT_NULL || ident_text == KW_LIT_TRUE || ident_text == KW_LIT_FALSE {
 
                    iter.consume();
 

	
 
                    // Parse builtin literal
 
                    let value = match ident_text {
 
                        KW_LIT_NULL => Literal::Null,
 
                        KW_LIT_TRUE => Literal::True,
 
                        KW_LIT_FALSE => Literal::False,
 
                        _ => unreachable!(),
 
                    };
 

	
 
                    ctx.heap.alloc_literal_expression(|this| LiteralExpression {
 
                        this,
 
                        span: ident_span,
 
                        value,
 
                        parent: ExpressionParent::None,
 
                        unique_id_in_definition: -1,
 
                    }).upcast()
 
                } else if ident_text == KW_LET {
 
                    // Binding expression
 
                    let keyword_span = iter.next_span();
 
                    iter.consume();
 

	
 
                    let bound_to = self.consume_prefix_expression(module, iter, ctx)?;
 
                    consume_token(&module.source, iter, TokenKind::Equal)?;
 
                    let bound_from = self.consume_prefix_expression(module, iter, ctx)?;
 

	
 
                    ctx.heap.alloc_binding_expression(|this| BindingExpression{
 
                        this,
 
                        span: keyword_span,
 
                        bound_to,
 
                        bound_from,
 
                        parent: ExpressionParent::None,
 
                        unique_id_in_definition: -1,
 
                    }).upcast()
 
                } else if ident_text == KW_CAST {
 
                    // Casting expression
 
                    iter.consume();
 
                    let to_type = if Some(TokenKind::OpenAngle) == iter.next() {
 
                        iter.consume();
 
                        let definition_id = self.cur_definition;
 
                        let poly_vars = ctx.heap[definition_id].poly_vars();
 
                        consume_parser_type(
 
                            &module.source, iter, &ctx.symbols, &ctx.heap,
 
                            poly_vars, SymbolScope::Module(module.root_id), definition_id,
 
                            true, 1
 
                        )?
 
                    } else {
 
                        // Automatic casting with inferred target type
 
                        ParserType{ elements: vec![ParserTypeElement{
 
                            full_span: ident_span, // TODO: @Span fix
 
                            variant: ParserTypeVariant::Inferred,
 
                        }]}
 
                    };
 

	
 
                    consume_token(&module.source, iter, TokenKind::OpenParen)?;
 
                    let subject = self.consume_expression(module, iter, ctx)?;
 
                    consume_token(&module.source, iter, TokenKind::CloseParen)?;
 

	
 
                    ctx.heap.alloc_cast_expression(|this| CastExpression{
 
                        this,
 
                        span: ident_span,
 
                        to_type,
 
                        subject,
 
                        parent: ExpressionParent::None,
 
                        unique_id_in_definition: -1,
 
                    }).upcast()
 
                } else {
 
                    // Not a builtin literal, but also not a known type. So we
 
                    // assume it is a variable expression. Although if we do,
 
                    // then if a programmer mistyped a struct/function name the
 
                    // error messages will be rather cryptic. For polymorphic
 
                    // arguments we can't really do anything at all (because it
 
                    // uses the '<' token). In the other cases we try to provide
 
                    // a better error message.
 
                    iter.consume();
 
                    let next = iter.next();
 
                    if Some(TokenKind::ColonColon) == next {
 
                        return Err(ParseError::new_error_str_at_span(&module.source, ident_span, "unknown identifier"));
 
                    } else if Some(TokenKind::OpenParen) == next {
 
                        return Err(ParseError::new_error_str_at_span(
 
                            &module.source, ident_span,
 
                            "unknown identifier, did you mistype a union variant's or a function's name?"
 
                        ));
 
                    } else if Some(TokenKind::OpenCurly) == next {
 
                        return Err(ParseError::new_error_str_at_span(
 
                            &module.source, ident_span,
 
                            "unknown identifier, did you mistype a struct type's name?"
 
                        ))
 
                    }
 

	
 
                    let ident_text = ctx.pool.intern(ident_text);
 
                    let identifier = Identifier { span: ident_span, value: ident_text };
 

	
 
                    ctx.heap.alloc_variable_expression(|this| VariableExpression {
 
                        this,
 
                        identifier,
 
                        declaration: None,
 
                        used_as_binding_target: false,
 
                        parent: ExpressionParent::None,
 
                        unique_id_in_definition: -1,
 
                    }).upcast()
 
                }
 
            }
 
        } else {
 
            return Err(ParseError::new_error_str_at_pos(
 
                &module.source, iter.last_valid_pos(), "expected an expression"
 
            ));
 
        };
 

	
 
        Ok(result)
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // Expression Utilities
 
    //--------------------------------------------------------------------------
 

	
 
    #[inline]
 
    fn consume_generic_binary_expression<
 
        M: Fn(Option<TokenKind>) -> Option<BinaryOperator>,
 
        F: Fn(&mut PassDefinitions, &Module, &mut TokenIter, &mut PassCtx) -> Result<ExpressionId, ParseError>
 
    >(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx, match_fn: M, higher_precedence_fn: F
 
    ) -> Result<ExpressionId, ParseError> {
 
        let mut result = higher_precedence_fn(self, module, iter, ctx)?;
 
        while let Some(operation) = match_fn(iter.next()) {
 
            let span = iter.next_span();
 
            iter.consume();
 

	
 
            let left = result;
 
            let right = higher_precedence_fn(self, module, iter, ctx)?;
 

	
 
            result = ctx.heap.alloc_binary_expression(|this| BinaryExpression{
 
                this, span, left, operation, right,
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast();
 
        }
 

	
 
        Ok(result)
 
    }
 

	
 
    #[inline]
 
    fn consume_expression_list(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx, end_pos: Option<&mut InputPosition>
 
    ) -> Result<Vec<ExpressionId>, ParseError> {
 
        let mut section = self.expressions.start_section();
 
        consume_comma_separated(
 
            TokenKind::OpenParen, TokenKind::CloseParen, &module.source, iter, ctx,
 
            |_source, iter, ctx| self.consume_expression(module, iter, ctx),
 
            &mut section, "an expression", "a list of expressions", end_pos
 
        )?;
 
        Ok(section.into_vec())
 
    }
 
}
 

	
 
/// Consumes a type. A type always starts with an identifier which may indicate
 
/// a builtin type or a user-defined type. The fact that it may contain
 
/// polymorphic arguments makes it a tree-like structure. Because we cannot rely
 
/// on knowing the exact number of polymorphic arguments we do not check for
 
/// these.
 
///
 
/// Note that the first depth index is used as a hack.
 
// TODO: @Optimize, @Span fix, @Cleanup
 
fn consume_parser_type(
 
    source: &InputSource, iter: &mut TokenIter, symbols: &SymbolTable, heap: &Heap, poly_vars: &[Identifier],
 
    cur_scope: SymbolScope, wrapping_definition: DefinitionId, allow_inference: bool, first_angle_depth: i32,
 
) -> Result<ParserType, ParseError> {
 
    struct Entry{
 
        element: ParserTypeElement,
 
        depth: i32,
 
    }
 

	
 
    // After parsing the array modified "[]", we need to insert an array type
 
    // before the most recently parsed type.
 
    fn insert_array_before(elements: &mut Vec<Entry>, depth: i32, span: InputSpan) {
 
        let index = elements.iter().rposition(|e| e.depth == depth).unwrap();
 
        elements.insert(index, Entry{
 
            element: ParserTypeElement{ full_span: span, variant: ParserTypeVariant::Array },
 
            depth,
 
        });
 
    }
 

	
 
    // Most common case we just have one type, perhaps with some array
 
    // annotations. This is both the hot-path, and simplifies the state machine
 
    // that follows and is responsible for parsing more complicated types.
 
    let element = consume_parser_type_ident(source, iter, symbols, heap, poly_vars, cur_scope, wrapping_definition, allow_inference)?;
 
    if iter.next() != Some(TokenKind::OpenAngle) {
 
        let num_embedded = element.variant.num_embedded();
 
        let mut num_array = 0;
 
        while iter.next() == Some(TokenKind::OpenSquare) {
 
            iter.consume();
 
            consume_token(source, iter, TokenKind::CloseSquare)?;
 
            num_array += 1;
 
        }
 

	
 
        let array_span = element.full_span;
 
        let mut elements = Vec::with_capacity(num_array + num_embedded + 1);
 
        for _ in 0..num_array {
 
            elements.push(ParserTypeElement{ full_span: array_span, variant: ParserTypeVariant::Array });
 
        }
 
        elements.push(element);
 

	
 
        if num_embedded != 0 {
 
            if !allow_inference {
 
                return Err(ParseError::new_error_str_at_span(source, array_span, "type inference is not allowed here"));
 
            }
 

	
 
            for _ in 0..num_embedded {
 
                elements.push(ParserTypeElement { full_span: array_span, variant: ParserTypeVariant::Inferred });
 
            }
 
        }
 

	
 
        for _ in 0..first_angle_depth {
 
            consume_token(source, iter, TokenKind::CloseAngle)?;
 
        }
 

	
 
        return Ok(ParserType{ elements });
 
    };
 

	
 
    // We have a polymorphic specification. So we start by pushing the item onto
 
    // our stack, then start adding entries together with the angle-brace depth
 
    // at which they're found.
 
    let mut elements = Vec::new();
 
    elements.push(Entry{ element, depth: 0 });
 

	
 
    // Start out with the first '<' consumed.
 
    iter.consume();
 
    enum State { Ident, Open, Close, Comma }
 
    let mut state = State::Open;
 
    let mut angle_depth = first_angle_depth + 1;
 

	
 
    loop {
 
        let next = iter.next();
src/protocol/parser/pass_tokenizer.rs
Show inline comments
 
use crate::protocol::input_source::{
 
    InputSource as InputSource,
 
    ParseError,
 
    InputPosition as InputPosition,
 
};
 

	
 
use super::tokens::*;
 
use super::token_parsing::*;
 

	
 
/// Tokenizer is a reusable parser to tokenize multiple source files using the
 
/// same allocated buffers. In a well-formed program, we produce a consistent
 
/// tree of token ranges such that we may identify tokens that represent a
 
/// defintion or an import before producing the entire AST.
 
///
 
/// If the program is not well-formed then the tree may be inconsistent, but we
 
/// will detect this once we transform the tokens into the AST. To ensure a
 
/// consistent AST-producing phase we will require the import to have balanced
 
/// curly braces
 
pub(crate) struct PassTokenizer {
 
    // Stack of input positions of opening curly braces, used to detect
 
    // unmatched opening braces, unmatched closing braces are detected
 
    // immediately.
 
    curly_stack: Vec<InputPosition>,
 
    // Points to an element in the `TokenBuffer.ranges` variable.
 
    stack_idx: usize,
 
}
 

	
 
impl PassTokenizer {
 
    pub(crate) fn new() -> Self {
 
        Self{
 
            curly_stack: Vec::with_capacity(32),
 
            stack_idx: 0
 
        }
 
    }
 

	
 
    pub(crate) fn tokenize(&mut self, source: &mut InputSource, target: &mut TokenBuffer) -> Result<(), ParseError> {
 
        // Assert source and buffer are at start
 
        debug_assert_eq!(source.pos().offset, 0);
 
        debug_assert!(target.tokens.is_empty());
 
        debug_assert!(target.ranges.is_empty());
 

	
 
        // Set up for tokenization by pushing the first range onto the stack.
 
        // This range may get transformed into the appropriate range kind later,
 
        // see `push_range` and `pop_range`.
 
        self.stack_idx = 0;
 
        target.ranges.push(TokenRange{
 
            parent_idx: NO_RELATION,
 
            range_kind: TokenRangeKind::Module,
 
            curly_depth: 0,
 
            start: 0,
 
            end: 0,
 
            num_child_ranges: 0,
 
            first_child_idx: NO_RELATION,
 
            last_child_idx: NO_RELATION,
 
            next_sibling_idx: NO_RELATION,
 
        });
 

	
 
        // Main tokenization loop
 
        while let Some(c) = source.next() {
 
            let token_index = target.tokens.len() as u32;
 

	
 
            if is_char_literal_start(c) {
 
                self.consume_char_literal(source, target)?;
 
            } else if is_string_literal_start(c) {
 
                self.consume_string_literal(source, target)?;
 
            } else if is_identifier_start(c) {
 
                let ident = self.consume_identifier(source, target)?;
 

	
 
                if demarks_definition(ident) {
 
                    self.push_range(target, TokenRangeKind::Definition, token_index);
 
                } else if demarks_import(ident) {
 
                    self.push_range(target, TokenRangeKind::Import, token_index);
 
                }
 
            } else if is_integer_literal_start(c) {
 
                self.consume_number(source, target)?;
 
            } else if is_pragma_start_or_pound(c) {
 
                let was_pragma = self.consume_pragma_or_pound(c, source, target)?;
 
                if was_pragma {
 
                    self.push_range(target, TokenRangeKind::Pragma, token_index);
 
                }
 
            } else if self.is_line_comment_start(c, source) {
 
                self.consume_line_comment(source, target)?;
 
            } else if self.is_block_comment_start(c, source) {
 
                self.consume_block_comment(source, target)?;
 
            } else if is_whitespace(c) {
 
                let contained_newline = self.consume_whitespace(source);
 
                if contained_newline {
 
                    let range = &target.ranges[self.stack_idx];
 
                    if range.range_kind == TokenRangeKind::Pragma {
 
                        self.pop_range(target, target.tokens.len() as u32);
 
                    }
 
                }
 
            } else {
 
                let was_punctuation = self.maybe_parse_punctuation(c, source, target)?;
 
                if let Some((token, token_pos)) = was_punctuation {
 
                    if token == TokenKind::OpenCurly {
 
                        self.curly_stack.push(token_pos);
 
                    } else if token == TokenKind::CloseCurly {
 
                        // Check if this marks the end of a range we're
 
                        // currently processing
 
                        if self.curly_stack.is_empty() {
 
                            return Err(ParseError::new_error_str_at_pos(
 
                                source, token_pos, "unmatched closing curly brace '}'"
 
                            ));
 
                        }
 

	
 
                        self.curly_stack.pop();
 

	
 
                        let range = &target.ranges[self.stack_idx];
 
                        if range.range_kind == TokenRangeKind::Definition && range.curly_depth == self.curly_stack.len() as u32 {
 
                            self.pop_range(target, target.tokens.len() as u32);
 
                        }
 

	
 
                        // Exit early if we have more closing curly braces than
 
                        // opening curly braces
 
                    } else if token == TokenKind::SemiColon {
 
                        // Check if this marks the end of an import
 
                        let range = &target.ranges[self.stack_idx];
 
                        if range.range_kind == TokenRangeKind::Import {
 
                            self.pop_range(target, target.tokens.len() as u32);
 
                        }
 
                    }
 
                } else {
 
                    return Err(ParseError::new_error_str_at_pos(
 
                        source, source.pos(), "unexpected character"
 
                    ));
 
                }
 
            }
 
        }
 

	
 
        // End of file, check if our state is correct
 
        if let Some(error) = source.had_error.take() {
 
            return Err(error);
 
        }
 

	
 
        if !self.curly_stack.is_empty() {
 
            // Let's not add a lot of heuristics and just tell the programmer
 
            // that something is wrong
 
            let last_unmatched_open = self.curly_stack.pop().unwrap();
 
            return Err(ParseError::new_error_str_at_pos(
 
                source, last_unmatched_open, "unmatched opening curly brace '{'"
 
            ));
 
        }
 

	
 
        // Ranges that did not depend on curly braces may have missing tokens.
 
        // So close all of the active tokens
 
        while self.stack_idx != 0 {
 
            self.pop_range(target, target.tokens.len() as u32);
 
        }
 

	
 
        // And finally, we may have a token range at the end that doesn't belong
 
        // to a range yet, so insert a "code" range if this is the case.
 
        debug_assert_eq!(self.stack_idx, 0);
 
        let last_registered_idx = target.ranges[0].end;
 
        let last_token_idx = target.tokens.len() as u32;
 
        if last_registered_idx != last_token_idx {
 
            self.add_code_range(target, 0, last_registered_idx, last_token_idx, NO_RELATION);
 
        }
 

	
 
        // TODO: @remove once I'm sure the algorithm works. For now it is better
 
        //  if the debugging is a little more expedient
 
        if cfg!(debug_assertions) {
 
            // For each range make sure its children make sense
 
            for parent_idx in 0..target.ranges.len() {
 
                let cur_range = &target.ranges[parent_idx];
 
                if cur_range.num_child_ranges == 0 {
 
                    assert_eq!(cur_range.first_child_idx, NO_RELATION);
 
                    assert_eq!(cur_range.last_child_idx, NO_RELATION);
 
                } else {
 
                    assert_ne!(cur_range.first_child_idx, NO_RELATION);
 
                    assert_ne!(cur_range.last_child_idx, NO_RELATION);
 

	
 
                    let mut child_counter = 0u32;
 
                    let mut last_valid_child_idx = cur_range.first_child_idx;
 
                    let mut child_idx = cur_range.first_child_idx;
 
                    while child_idx != NO_RELATION {
 
                        let child_range = &target.ranges[child_idx as usize];
 
                        assert_eq!(child_range.parent_idx, parent_idx as i32);
 
                        last_valid_child_idx = child_idx;
 
                        child_idx = child_range.next_sibling_idx;
 
                        child_counter += 1;
 
                    }
 

	
 
                    assert_eq!(cur_range.last_child_idx, last_valid_child_idx);
 
                    assert_eq!(cur_range.num_child_ranges, child_counter);
 
                }
 
            }
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn is_line_comment_start(&self, first_char: u8, source: &InputSource) -> bool {
 
        return first_char == b'/' && Some(b'/') == source.lookahead(1);
 
    }
 

	
 
    fn is_block_comment_start(&self, first_char: u8, source: &InputSource) -> bool {
 
        return first_char == b'/' && Some(b'*') == source.lookahead(1);
 
    }
 

	
 
    fn maybe_parse_punctuation(
 
        &mut self, first_char: u8, source: &mut InputSource, target: &mut TokenBuffer
 
    ) -> Result<Option<(TokenKind, InputPosition)>, ParseError> {
 
        debug_assert!(first_char != b'#', "'#' needs special handling");
 
        debug_assert!(first_char != b'\'', "'\'' needs special handling");
 
        debug_assert!(first_char != b'"', "'\"' needs special handling");
 

	
 
        let pos = source.pos();
 
        let token_kind;
 
        if first_char == b'!' {
 
            source.consume();
 
            if Some(b'=') == source.next() {
 
                source.consume();
 
                token_kind = TokenKind::NotEqual;
 
            } else {
 
                token_kind = TokenKind::Exclamation;
 
            }
 
        } else if first_char == b'%' {
 
            source.consume();
 
            if Some(b'=') == source.next() {
 
                source.consume();
 
                token_kind = TokenKind::PercentEquals;
 
            } else {
 
                token_kind = TokenKind::Percent;
 
            }
 
        } else if first_char == b'&' {
 
            source.consume();
 
            let next = source.next();
 
            if Some(b'&') == next {
 
                source.consume();
 
                token_kind = TokenKind::AndAnd;
 
            } else if Some(b'=') == next {
 
                source.consume();
 
                token_kind = TokenKind::AndEquals;
 
            } else {
 
                token_kind = TokenKind::And;
 
            }
 
        } else if first_char == b'(' {
 
            source.consume();
 
            token_kind = TokenKind::OpenParen;
 
        } else if first_char == b')' {
 
            source.consume();
 
            token_kind = TokenKind::CloseParen;
 
        } else if first_char == b'*' {
 
            source.consume();
 
            if let Some(b'=') = source.next() {
 
                source.consume();
 
                token_kind = TokenKind::StarEquals;
 
            } else {
 
                token_kind = TokenKind::Star;
 
            }
 
        } else if first_char == b'+' {
 
            source.consume();
 
            let next = source.next();
 
            if Some(b'+') == next {
 
                source.consume();
 
                token_kind = TokenKind::PlusPlus;
 
            } else if Some(b'=') == next {
 
                source.consume();
 
                token_kind = TokenKind::PlusEquals;
 
            } else {
 
                token_kind = TokenKind::Plus;
 
            }
 
        } else if first_char == b',' {
 
            source.consume();
 
            token_kind = TokenKind::Comma;
 
        } else if first_char == b'-' {
 
            source.consume();
 
            let next = source.next();
 
            if Some(b'-') == next {
 
                source.consume();
 
                token_kind = TokenKind::MinusMinus;
 
            } else if Some(b'>') == next {
 
                source.consume();
 
                token_kind = TokenKind::ArrowRight;
 
            } else if Some(b'=') == next {
 
                source.consume();
 
                token_kind = TokenKind::MinusEquals;
 
            } else {
 
                token_kind = TokenKind::Minus;
 
            }
 
        } else if first_char == b'.' {
 
            source.consume();
 
            if let Some(b'.') = source.next() {
 
                source.consume();
 
                token_kind = TokenKind::DotDot;
 
            } else {
 
                token_kind = TokenKind::Dot
 
            }
 
        } else if first_char == b'/' {
 
            source.consume();
 
            debug_assert_ne!(Some(b'/'), source.next());
 
            debug_assert_ne!(Some(b'*'), source.next());
 
            if let Some(b'=') = source.next() {
 
                source.consume();
 
                token_kind = TokenKind::SlashEquals;
 
            } else {
 
                token_kind = TokenKind::Slash;
 
            }
 
        } else if first_char == b':' {
 
            source.consume();
 
            if let Some(b':') = source.next() {
 
                source.consume();
 
                token_kind = TokenKind::ColonColon;
 
            } else {
 
                token_kind = TokenKind::Colon;
 
            }
 
        } else if first_char == b';' {
 
            source.consume();
 
            token_kind = TokenKind::SemiColon;
 
        } else if first_char == b'<' {
 
            source.consume();
 
            let next = source.next();
 
            if let Some(b'<') = next {
 
                source.consume();
 
                if let Some(b'=') = source.next() {
 
                    source.consume();
 
                    token_kind = TokenKind::ShiftLeftEquals;
 
                } else {
 
                    token_kind = TokenKind::ShiftLeft;
 
                }
 
            } else if let Some(b'=') = next {
 
                source.consume();
 
                token_kind = TokenKind::LessEquals;
 
            } else {
 
                token_kind = TokenKind::OpenAngle;
 
            }
 
        } else if first_char == b'=' {
 
            source.consume();
 
            if let Some(b'=') = source.next() {
 
                source.consume();
 
                token_kind = TokenKind::EqualEqual;
 
            } else {
 
                token_kind = TokenKind::Equal;
 
            }
 
        } else if first_char == b'>' {
 
            source.consume();
 
            let next = source.next();
 
            if Some(b'>') == next {
 
                source.consume();
 
                if Some(b'=') == source.next() {
 
                    source.consume();
 
                    token_kind = TokenKind::ShiftRightEquals;
 
                } else {
 
                    token_kind = TokenKind::ShiftRight;
 
                }
 
            } else if Some(b'=') == next {
 
                source.consume();
 
                token_kind = TokenKind::GreaterEquals;
 
            } else {
 
                token_kind = TokenKind::CloseAngle;
 
            }
 
        } else if first_char == b'?' {
 
            source.consume();
 
            token_kind = TokenKind::Question;
 
        } else if first_char == b'@' {
 
            source.consume();
 
            if let Some(b'=') = source.next() {
 
                source.consume();
 
                token_kind = TokenKind::AtEquals;
 
            } else {
 
                token_kind = TokenKind::At;
 
            }
 
        } else if first_char == b'[' {
 
            source.consume();
 
            token_kind = TokenKind::OpenSquare;
 
        } else if first_char == b']' {
 
            source.consume();
 
            token_kind = TokenKind::CloseSquare;
 
        } else if first_char == b'^' {
 
            source.consume();
 
            if let Some(b'=') = source.next() {
 
                source.consume();
 
                token_kind = TokenKind::CaretEquals;
 
            } else {
 
                token_kind = TokenKind::Caret;
 
            }
 
        } else if first_char == b'{' {
 
            source.consume();
 
            token_kind = TokenKind::OpenCurly;
 
        } else if first_char == b'|' {
 
            source.consume();
 
            let next = source.next();
 
            if Some(b'|') == next {
 
                source.consume();
 
                token_kind = TokenKind::OrOr;
 
            } else if Some(b'=') == next {
 
                source.consume();
 
                token_kind = TokenKind::OrEquals;
 
            } else {
 
                token_kind = TokenKind::Or;
 
            }
 
        } else if first_char == b'}' {
 
            source.consume();
 
            token_kind = TokenKind::CloseCurly;
 
        } else if first_char == b'~' {
 
            source.consume();
 
            token_kind = TokenKind::Tilde;
 
        } else {
 
            self.check_ascii(source)?;
 
            return Ok(None);
 
        }
 

	
 
        target.tokens.push(Token::new(token_kind, pos));
 
        Ok(Some((token_kind, pos)))
 
    }
 

	
 
    fn consume_char_literal(&mut self, source: &mut InputSource, target: &mut TokenBuffer) -> Result<(), ParseError> {
 
        let begin_pos = source.pos();
 

	
 
        // Consume the leading quote
 
        debug_assert!(source.next().unwrap() == b'\'');
 
        source.consume();
 

	
 
        let mut prev_char = b'\'';
 
        while let Some(c) = source.next() {
 
            if !c.is_ascii() {
 
                return Err(ParseError::new_error_str_at_pos(source, source.pos(), "non-ASCII character in char literal"));
 
            }
 
            source.consume();
 

	
 
            // Make sure ending quote was not escaped
 
            if c == b'\'' && prev_char != b'\\' {
 
                prev_char = c;
 
                break;
 
            }
 

	
 
            prev_char = c;
 
        }
 

	
 
        if prev_char != b'\'' {
 
            // Unterminated character literal, reached end of file.
 
            return Err(ParseError::new_error_str_at_pos(source, begin_pos, "encountered unterminated character literal"));
 
        }
 

	
 
        let end_pos = source.pos();
 

	
 
        target.tokens.push(Token::new(TokenKind::Character, begin_pos));
 
        target.tokens.push(Token::new(TokenKind::SpanEnd, end_pos));
 

	
 
        Ok(())
 
    }
 

	
 
    fn consume_string_literal(&mut self, source: &mut InputSource, target: &mut TokenBuffer) -> Result<(), ParseError> {
 
        let begin_pos = source.pos();
 

	
 
        // Consume the leading double quotes
 
        debug_assert!(source.next().unwrap() == b'"');
 
        source.consume();
 

	
 
        let mut prev_char = b'"';
 
        while let Some(c) = source.next() {
 
            if !c.is_ascii() {
 
                return Err(ParseError::new_error_str_at_pos(source, source.pos(), "non-ASCII character in string literal"));
 
            }
 

	
 
            source.consume();
 
            if c == b'"' && prev_char != b'\\' {
 
                prev_char = c;
 
                break;
 
            }
 

	
 
            prev_char = c;
 
        }
 

	
 
        if prev_char != b'"' {
 
            // Unterminated string literal
 
            return Err(ParseError::new_error_str_at_pos(source, begin_pos, "encountered unterminated string literal"));
 
        }
 

	
 
        let end_pos = source.pos();
 
        target.tokens.push(Token::new(TokenKind::String, begin_pos));
 
        target.tokens.push(Token::new(TokenKind::SpanEnd, end_pos));
 

	
 
        Ok(())
 
    }
 

	
 
    fn consume_pragma_or_pound(&mut self, first_char: u8, source: &mut InputSource, target: &mut TokenBuffer) -> Result<bool, ParseError> {
 
        let start_pos = source.pos();
 
        debug_assert_eq!(first_char, b'#');
 
        source.consume();
 

	
 
        let next = source.next();
 
        if next.is_none() || !is_identifier_start(next.unwrap()) {
 
            // Just a pound sign
 
            target.tokens.push(Token::new(TokenKind::Pound, start_pos));
 
            Ok(false)
 
        } else {
 
            // Pound sign followed by identifier
 
            source.consume();
 
            while let Some(c) = source.next() {
 
                if !is_identifier_remaining(c) {
 
                    break;
 
                }
 
                source.consume();
 
            }
 

	
 
            self.check_ascii(source)?;
 

	
 
            let end_pos = source.pos();
 
            target.tokens.push(Token::new(TokenKind::Pragma, start_pos));
 
            target.tokens.push(Token::new(TokenKind::SpanEnd, end_pos));
 
            Ok(true)
 
        }
 
    }
 

	
 
    fn consume_line_comment(&mut self, source: &mut InputSource, target: &mut TokenBuffer) -> Result<(), ParseError> {
 
        let begin_pos = source.pos();
 

	
 
        // Consume the leading "//"
 
        debug_assert!(source.next().unwrap() == b'/' && source.lookahead(1).unwrap() == b'/');
 
        source.consume();
 
        source.consume();
 

	
 
        let mut prev_char = b'/';
 
        let mut cur_char = b'/';
 
        while let Some(c) = source.next() {
 
            prev_char = cur_char;
 
            cur_char = c;
 

	
 
            if c == b'\n' {
 
                // End of line, note that the newline is not consumed
 
                break;
 
            }
 

	
 
            source.consume();
 
        }
 

	
 
        let mut end_pos = source.pos();
 
        debug_assert_eq!(begin_pos.line, end_pos.line);
 

	
 
        // Modify offset to not include the newline characters
 
        if cur_char == b'\n' {
 
            if prev_char == b'\r' {
 
                end_pos.offset -= 2;
 
            } else {
 
                end_pos.offset -= 1;
 
            }
 
            // Consume final newline
 
            source.consume();
 
        } else {
 
            // End of comment was due to EOF
 
            debug_assert!(source.next().is_none())
 
        }
 

	
 
        target.tokens.push(Token::new(TokenKind::LineComment, begin_pos));
 
        target.tokens.push(Token::new(TokenKind::SpanEnd, end_pos));
 

	
 
        Ok(())
 
    }
 

	
 
    fn consume_block_comment(&mut self, source: &mut InputSource, target: &mut TokenBuffer) -> Result<(), ParseError> {
 
        let begin_pos = source.pos();
 

	
 
        // Consume the leading "/*"
 
        debug_assert!(source.next().unwrap() == b'/' && source.lookahead(1).unwrap() == b'*');
 
        source.consume();
 
        source.consume();
 

	
 
        // Explicitly do not put prev_char at "*", because then "/*/" would
 
        // represent a valid and closed block comment
 
        let mut prev_char = b' ';
 
        let mut is_closed = false;
 
        while let Some(c) = source.next() {
 
            source.consume();
 
            if prev_char == b'*' && c == b'/' {
 
                // End of block comment
 
                is_closed = true;
 
                break;
 
            }
 
            prev_char = c;
 
        }
 

	
 
        if !is_closed {
 
            return Err(ParseError::new_error_str_at_pos(
 
                source, source.pos(), "encountered unterminated block comment")
 
            );
 
        }
 

	
 
        let end_pos = source.pos();
 
        target.tokens.push(Token::new(TokenKind::BlockComment, begin_pos));
 
        target.tokens.push(Token::new(TokenKind::SpanEnd, end_pos));
 

	
 
        Ok(())
 
    }
 

	
 
    fn consume_identifier<'a>(&mut self, source: &'a mut InputSource, target: &mut TokenBuffer) -> Result<&'a [u8], ParseError> {
 
        let begin_pos = source.pos();
 
        debug_assert!(is_identifier_start(source.next().unwrap()));
 
        source.consume();
 

	
 
        // Keep reading until no more identifier
 
        while let Some(c) = source.next() {
 
            if !is_identifier_remaining(c) {
 
                break;
 
            }
 

	
 
            source.consume();
 
        }
 
        self.check_ascii(source)?;
 

	
 
        let end_pos = source.pos();
 
        target.tokens.push(Token::new(TokenKind::Ident, begin_pos));
 
        target.tokens.push(Token::new(TokenKind::SpanEnd, end_pos));
 
        Ok(source.section_at_pos(begin_pos, end_pos))
 
    }
 

	
 
    fn consume_number(&mut self, source: &mut InputSource, target: &mut TokenBuffer) -> Result<(), ParseError> {
 
        let begin_pos = source.pos();
 
        debug_assert!(is_integer_literal_start(source.next().unwrap()));
 
        source.consume();
 

	
 
        // Keep reading until it doesn't look like a number anymore
 
        while let Some(c) = source.next() {
 
            if !maybe_number_remaining(c) {
 
                break;
 
            }
 

	
 
            source.consume();
 
        }
 
        self.check_ascii(source)?;
 

	
 
        let end_pos = source.pos();
 
        target.tokens.push(Token::new(TokenKind::Integer, begin_pos));
 
        target.tokens.push(Token::new(TokenKind::SpanEnd, end_pos));
 

	
 
        Ok(())
 
    }
 

	
 
    // Consumes whitespace and returns whether or not the whitespace contained
 
    // a newline.
 
    fn consume_whitespace(&self, source: &mut InputSource) -> bool {
 
        debug_assert!(is_whitespace(source.next().unwrap()));
 

	
 
        let mut has_newline = false;
 
        while let Some(c) = source.next() {
 
            if !is_whitespace(c) {
 
                break;
 
            }
 

	
 
            if c == b'\n' {
 
                has_newline = true;
 
            }
 
            source.consume();
 
        }
 

	
 
        has_newline
 
    }
 

	
 
    fn add_code_range(
 
        &mut self, target: &mut TokenBuffer, parent_idx: i32,
 
        code_start_idx: u32, code_end_idx: u32, next_sibling_idx: i32
 
    ) {
 
        let new_range_idx = target.ranges.len() as i32;
 
        let parent_range = &mut target.ranges[parent_idx as usize];
 
        debug_assert_ne!(parent_range.end, code_end_idx, "called push_code_range without a need to do so");
 

	
 
        let sibling_idx = parent_range.last_child_idx;
 

	
 
        parent_range.last_child_idx = new_range_idx;
 
        parent_range.end = code_end_idx;
 
        parent_range.num_child_ranges += 1;
 

	
 
        let curly_depth = self.curly_stack.len() as u32;
 
        target.ranges.push(TokenRange{
 
            parent_idx,
 
            range_kind: TokenRangeKind::Code,
 
            curly_depth,
 
            start: code_start_idx,
 
            end: code_end_idx,
 
            num_child_ranges: 0,
 
            first_child_idx: NO_RELATION,
 
            last_child_idx: NO_RELATION,
 
            next_sibling_idx,
 
        });
 

	
 
        // Fix up the sibling indices
 
        if sibling_idx != NO_RELATION {
 
            let sibling_range = &mut target.ranges[sibling_idx as usize];
 
            sibling_range.next_sibling_idx = new_range_idx;
 
        }
 
    }
 

	
 
    fn push_range(&mut self, target: &mut TokenBuffer, range_kind: TokenRangeKind, first_token_idx: u32) {
 
        let new_range_idx = target.ranges.len() as i32;
 
        let parent_idx = self.stack_idx as i32;
 
        let parent_range = &mut target.ranges[self.stack_idx];
 

	
 
        if parent_range.first_child_idx == NO_RELATION {
 
            parent_range.first_child_idx = new_range_idx;
 
        }
 

	
 
        let last_registered_idx = parent_range.end;
 
        if last_registered_idx != first_token_idx {
 
            self.add_code_range(target, parent_idx, last_registered_idx, first_token_idx, new_range_idx + 1);
 
        }
 

	
 
        // Push the new range
 
        self.stack_idx = target.ranges.len();
 
        let curly_depth = self.curly_stack.len() as u32;
 
        target.ranges.push(TokenRange{
 
            parent_idx,
 
            range_kind,
 
            curly_depth,
 
            start: first_token_idx,
 
            end: first_token_idx, // modified when popped
 
            num_child_ranges: 0,
 
            first_child_idx: NO_RELATION,
 
            last_child_idx: NO_RELATION,
 
            next_sibling_idx: NO_RELATION
 
        })
 
    }
 

	
 
    fn pop_range(&mut self, target: &mut TokenBuffer, end_token_idx: u32) {
 
        let popped_idx = self.stack_idx as i32;
 
        let popped_range = &mut target.ranges[self.stack_idx];
 
        debug_assert!(self.stack_idx != 0, "attempting to pop top-level range");
 

	
 
        // Fix up the current range before going back to parent
 
        popped_range.end = end_token_idx;
 
        debug_assert_ne!(popped_range.start, end_token_idx);
 

	
 
        // Go back to parent and fix up its child pointers, but remember the
 
        // last child, so we can link it to the newly popped range.
 
        self.stack_idx = popped_range.parent_idx as usize;
 
        let parent = &mut target.ranges[self.stack_idx];
 
        if parent.first_child_idx == NO_RELATION {
 
            parent.first_child_idx = popped_idx;
 
        }
 
        let prev_sibling_idx = parent.last_child_idx;
 
        parent.last_child_idx = popped_idx;
 
        parent.end = end_token_idx;
 
        parent.num_child_ranges += 1;
 

	
 
        // Fix up the sibling (if it exists)
 
        if prev_sibling_idx != NO_RELATION {
 
            let sibling = &mut target.ranges[prev_sibling_idx as usize];
 
            sibling.next_sibling_idx = popped_idx;
 
        }
 
    }
 

	
 

	
 
    fn check_ascii(&self, source: &InputSource) -> Result<(), ParseError> {
 
        match source.next() {
 
            Some(c) if !c.is_ascii() => {
 
                Err(ParseError::new_error_str_at_pos(source, source.pos(), "encountered a non-ASCII character"))
 
            },
 
            _else => {
 
                Ok(())
 
            },
 
        }
 
    }
 
}
 

	
 
// Helpers for characters
 
fn demarks_definition(ident: &[u8]) -> bool {
 
    return
 
        ident == KW_STRUCT ||
 
            ident == KW_ENUM ||
 
            ident == KW_UNION ||
 
            ident == KW_FUNCTION ||
 
            ident == KW_PRIMITIVE ||
 
            ident == KW_COMPOSITE
 
}
 

	
 
fn demarks_import(ident: &[u8]) -> bool {
 
    return ident == KW_IMPORT;
 
}
 

	
 
fn is_whitespace(c: u8) -> bool {
 
    c.is_ascii_whitespace()
 
}
 

	
 
fn is_char_literal_start(c: u8) -> bool {
 
    return c == b'\'';
 
}
 

	
 
fn is_string_literal_start(c: u8) -> bool {
 
    return c == b'"';
 
}
 

	
 
fn is_pragma_start_or_pound(c: u8) -> bool {
 
    return c == b'#';
 
}
 

	
 
fn is_identifier_start(c: u8) -> bool {
 
    return
 
        (c >= b'a' && c <= b'z') ||
 
            (c >= b'A' && c <= b'Z') ||
 
            c == b'_'
 
}
 

	
 
fn is_identifier_remaining(c: u8) -> bool {
 
    return
 
        (c >= b'0' && c <= b'9') ||
 
            (c >= b'a' && c <= b'z') ||
 
            (c >= b'A' && c <= b'Z') ||
 
            c == b'_'
 
}
 

	
 
fn is_integer_literal_start(c: u8) -> bool {
 
    return c >= b'0' && c <= b'9';
 
}
 

	
 
fn maybe_number_remaining(c: u8) -> bool {
 
    // Note: hex range includes the possible binary indicator 'b' and 'B';
 
    return
 
        (c == b'o' || c == b'O' || c == b'x' || c == b'X') ||
 
            (c >= b'0' && c <= b'9') || (c >= b'A' && c <= b'F') || (c >= b'a' && c <= b'f') ||
 
            c == b'_';
 
}
 

	
 
#[cfg(test)]
 
mod tests {
 
    use super::*;
 

	
 
    // TODO: Remove at some point
 
    #[test]
 
    fn test_tokenizer() {
 
        let mut source = InputSource::new_test("
 

	
 
        #version 500
 
        # hello 2
 

	
 
        import std.reo::*;
 

	
 
        struct Thing {
 
            int a: 5,
 
        }
 
        enum Hello {
 
            A,
 
            B
 
        }
 

	
 
        // Hello hello, is it me you are looking for?
 
        // I can seee it in your eeeyes
 

	
 
        func something(int a, int b, int c) -> byte {
 
            int a = 5;
 
            struct Inner {
 
                int a
 
            }
 
            struct City {
 
                int b
 
            }
 
            /* Waza
 
            How are you doing
 
            Things in here yo
 
            /* */ */
 

	
 
            a = a + 5 * 2;
 
            struct Pressure {
 
                int d
 
            }
 
        }
 
        ");
 
        let mut t = PassTokenizer::new();
 
        let mut buffer = TokenBuffer::new();
 
        t.tokenize(&mut source, &mut buffer).expect("tokenize");
 

	
 
        println!("Ranges:\n");
 
        for (idx, range) in buffer.ranges.iter().enumerate() {
 
            println!("[{}] {:?}", idx, range)
 
        }
 

	
 
        println!("Tokens:\n");
 
        let mut iter = buffer.tokens.iter().enumerate();
 
        while let Some((idx, token)) = iter.next() {
 
            match token.kind {
 
                TokenKind::Ident | TokenKind::Pragma | TokenKind::Integer |
 
                TokenKind::String | TokenKind::Character | TokenKind::LineComment |
 
                TokenKind::BlockComment => {
 
                    let (_, end) = iter.next().unwrap();
 
                    println!("[{}] {:?} ......", idx, token.kind);
 
                    assert_eq!(end.kind, TokenKind::SpanEnd);
 
                    let text = source.section_at_pos(token.pos, end.pos);
 
                    println!("{}", String::from_utf8_lossy(text));
 
                },
 
                _ => {
 
                    println!("[{}] {:?}", idx, token.kind);
 
                }
 
            }
 
        }
 
    }
 
}
 
\ No newline at end of file

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